The cumene-to-phenol process is described in more detail in this chapter. An overview is given about synthetic routes via direct oxidation of benzene. None of these alternative routes has been commercialized. The chapter also gives an overview of global supply and use of phenol in Finally, the main natural sources and synthetic routes for cresols, xylenols, resorcinol, and bisphenol-A are described. These components are used as comonomers for special phenolic resins.
Weber and M. Weber Diisopropylbenzene Dimethyl benzyl alcohol Hydrogen Water Hydrogen peroxide Mesityloxide Maximale Arbeitsplatzkonzentration Methyl hydroperoxide Melting point Molecular weight Caustic soda Sodium phenate Ammonia Nitrogen oxides Nitrous oxide Permissible exposure limit Self-Accelerating-Decomposition-Temperature Triisopropylbenzene Time weighted averages over 8 h Phenols are aromatic components which contain one or more hydroxyl groups that are attached to an aromatic ring.
For the production of phenolic resins, mostly mono-hydroxybenzenes, especially phenol, are of the greatest importance. Besides alkylphenols cresols and xylenols , resorcinol di-hydroxybenzene and bisphenolA are used sparingly for the production of phenolic resins.
In Table 2. Compared to aliphatic alcohols, phenols are weak acids. Thus, phenols can be easily extracted from organic solutions with aqueous sodium hydroxide. This is the preferred method to recover phenol and cresols from coal tar [1]. Table 2. Presently, a small amount of phenol is still obtained from coal tar. Yet in , Felix Hoffmann filed his patent [2] for the synthesis of acetylsalicylic acid Aspirin , which required phenol as starting material.
At the dawn of the twentieth century, the demand for phenol grew significantly with the commercialization of the phenolic resins Bakelite. Leo Baekeland launched his first phenolic resins plant in May in Germany since phenol was readily available from coal tar. Much later the use for bisphenol-A polycarbonates and epoxide resins became an important factor for the substantial market growth of phenol.
Synthetic routes were developed at the end of the nineteenth century to meet the increasing demand for phenol. The first synthetic method for the production of phenol involved sulfonation and later chlorination of benzene.
Details are described in [3]. These processes are no longer used for the commercial production of phenol. After the Second World War, the cumene-to-phenol process Hock-Process was developed and commercialized. It is currently the predominate route for the production of phenol.
Details are described in Sect. In the s, the first commercial plant using toluene as the feedstock was launched. The process was developed simultaneously by Dow [4] and the California Research Corp. The process is described in more detail in [6]. However, all commercial plants were closed in Currently, there is no commercial production of phenol from toluene. Several attempts have been explored during the past two decades to synthesize phenol via the direct oxidation of benzene.
Unlike the cumene process route, the direct oxidation of benzene does not produce acetone as a co-product and offers the potential for economy of operation without by-product. One route is the direct oxidation of benzene with nitrous oxide N2O, which was mainly developed by Solutia in cooperation with the Boreskov Institute of Catalysis in Russia [7, 8]. The greenhouse gas N2O is a main component in the off-gas from the adipic acid production. Its use for the phenol production would therefore be ideally suited to the adipic acid manufacturers.
However, the off-gas requires careful purification to remove various nitrogen oxides NOx and oxygen. As an alternative, N2O could be produced deliberately by catalytic oxidation of ammonia NH3 with air [8] without relying on it as a by-product from adipic acid plants. In [9—11], an overview is presented on the use of oxygen or hydrogen peroxide H2O2 for the direct oxidation of benzene with various catalysts. When using oxygen, the benzene conversion is limited to only several per cent due to low selectivities.
With hydrogen peroxide, higher conversion rates should be possible. For example, Bianchi et al. None of the above described routes via direct oxidation of benzene have been commercialized. The use of either NH3 or H2O2 is questionable since both are valuable chemical intermediates, and their role as oxygen carriers must be considered in any economical assessment of a direct oxidation of benzene to phenol.
At ambient temperatures, phenol is a solid and appears as a white amorphous material. It possesses a melting point of In the molten state, pure phenol is a clear, colorless liquid. When exposed to air, phenol rapidly turns to a pink color due to certain trace impurities such as iron and copper that are present in its production process or during storage.
At temperatures below Phenol is soluble in aromatic hydrocarbons, alcohols, ketones, ethers, acids, and halogenated hydrocarbons. It is less soluble in aliphatic hydrocarbons. Phenol forms azeotropic mixtures with water, cumene, and a-methylstyrene AMS as reported in reference [13].
They are due to the presence of a hydroxyl group and an aromatic ring which are complementary to each other in facilitating both electrophilic and nucleophilic type of reactions. Phenol has an extremely high reactivity of its ring toward electrophilic substitution and assists its acid catalyzed reaction with formaldehyde leading to phenolic resins. Further phenol is a weak acid and readily forms sodium phenate NaPh. In the presence of NaPh, nucleophilic addition of the phenolic aromatic ring to the carbonyl group of formaldehyde occurs.
A base catalyzes the reaction by converting phenol into the more reactive more nucleophilic phenate or phenoxide ion for reaction with formaldehyde - see Chap. The unshared electron pair located on the hydroxyl group is delocalized over the aromatic ring leading to an electron excess at the ortho and para positions.
Classical electrophilic reactions are halogenation, sulfonation, and nitration. The reaction of bromine in aqueous solution results in 2,4,6-tribromophenol in high yields. Under special conditions acid catalysts facilitate the conversion of phenol with formaldehyde to bisphenol-F or reaction of acetone to bisphenol-A.
Phenol can be hydrogenated on palladium catalysts to cyclohexanone with high selectivities [14, 15]. Cyclohexanone is the feedstock for the production of caprolactame monomer for Nylon 6. The process was first reported by Hock and Lang [16], see Sects. Cumene is oxidized with oxygen from air to form cumene hydroperoxide CHP.
The peroxide is subsequently decomposed to phenol 14 M. Weber and acetone, using a strong mineral acid as a catalyst. Figure 2. Cumene as a feedstock for this process is produced from benzene and propylene.
Formerly the alkylation reaction was carried out in solution with acidic catalysts like phosphoric acids and aluminium chloride. Currently, most of the cumene is produced commercially with heterogeneous zeolite catalysts.
Details are described in [17]. The first production plant was commenced in in Shawinigan, Canada. Although all these processes use the principles of the Hock synthesis, there are differences in the design and operation of the reaction units and the distillation unit. The production was initiated in with a capacity of 8, tons phenol per year. In , a new plant was started up in Antwerp, Belgium. After several expansions, the capacity is currently 2 Phenols 15 Fig. In , yet another plant was placed into operation in Mobile, Alabama.
Referring back to Fig. Fresh and recycle cumene flow through a cascade of large bubble columns. Air is 16 M. Weber added at the bottom of each reactor. Oxygen transfers from the air bubbles into the cumene. The reaction in the liquid phase proceeds by a complex radical mechanism [18].
The reaction is auto-catalyzed by CHP. The liquid phase in such large reactors is intensively mixed by the rising gas bubbles. This mixing characteristic plays a critical role in conversion rates and yields [19]. The bubble columns operate at pressures ranging from atmospheric to around kPa.
The residence time in the reactors is several hours. The temperature is controlled by internal or external heat exchangers. Several by-products are formed in the oxidation step. ACP leaves the process with the high boilers from the distillation unit. It can also be recovered as a pure product. Other by-products are formic and acetic acid.
Small amounts of methyl hydroperoxide MHP are formed and removed with the off-gas. Phenol is a strong inhibitor for the oxidation reaction. Any recycle cumene must be treated to remove even small traces of phenol. From a safety point of view, great care is required in the design of the air inlet devices sparger at the bottom of the reactors.
Any backflow of peroxide containing liquid into the air line must be avoided. It is also important to monitor and ensure a low final concentration of oxygen in the off-gas at the top.
This is to avoid an explosive mixture in the gas phase and in the subsequent units for the off-gas treatment [20]. Another important aspect is thermal stability of a reactor after a shut-down.
It is important to know at what temperature a reactor has to be cooled down to avoid subsequent heating up from the ongoing exothermic decomposition of CHP. Residual impurities can be removed from the off-gas with activated carbon adsorbers [21] or with regenerative thermal oxidizers [22].
Off-gas, which is purified under pressure on activated carbon, can be used as technical grade nitrogen for blanketing or venting of process equipment. It can also be used to dry adsorbers after regeneration with steam.
Besides cumene, the water phase is condensed from the off-gas, in which MHP is present. After treatment with diluted caustic soda, the cumene is recycled to the oxidation unit. Disposal of MHP in the aqueous stream is not allowed since it is toxic to fish. The water is then sent to a biological waste water treatment BWWT. This is accomplished in a one- or multiple-step vacuum distillation, the so-called concentration unit. Highly efficient structured packings are used in these columns.
Fresh cumene can be used for reflux. The distilled and recycled cumene is washed with diluted caustic soda to remove organic acids and traces of phenol.
Therefore, a certain amount of pressurized cumene, so-called flush cumene, must be available at all times. The first part of the cleavage unit is a circulation loop. One or several heat exchangers are installed as reactors within the loop.
Small amounts of sulphuric acid are used as the catalyst. CHP is added to the loop and is spontaneously diluted with the product from the reaction which is mainly phenol, acetone, and residual cumene. In the event of a shut down, the injection point is flushed with cumene to separate CHP from acidic cleavage product in the loop. CHP decomposes while passing through the heat exchanger.
DMBA is partially dehydrated to AMS, which reacts in consecutive reactions with phenol to high-boiling cumylphenols, see below. AMS also forms high-boiling dimers. Other by-products are hydroxyacetone from the reaction of CHP and acetone, 2-methylbenzofurane 2-MBF from the reaction of hydroxyacetone with phenol, diacetone alcohol from the self-condensation of acetone, and mesityloxide MOX from the dehydration of diacetone alcohol.
Some aldehydes are also formed, especially acetaldehyde. All these by-products require special conditions in the distillation unit to separate them from phenol and acetone. An overview of all these reactions is given in [23]. The temperature is increased by adding again CHP [24] or by indirect heating with steam. The product from the cleavage unit is cooled. All acid-catalyzed reactions from AMS are stopped by adding sodium phenate NaPh in the neutralization unit.
Additional sulphuric acid may be needed if excess NaPh needs to be decomposed to recover phenol. Salts from organic acids, mainly sodium sulphate from the decomposition of NaPh, are extracted in the aqueous phase. This process water is further treated in the phenol removal unit to recover phenol by liquid-liquid extraction with cumene as the extraction solvent.
Phenol is recovered from the cumene as NaPh by washing with caustic soda in a separate scrubber. Parts of the cumene in the phenol removal unit may be refreshed with purified recycle cumene or fresh cumene. NaPh and discharged cumene are routed to the neutralization unit. The process water is finally treated in a water stripper to remove dissolved acetone and cumene.
The product from the neutralisation unit is sent to the distillation unit. In the crude acetone column, acetone and some water are separated as the top product. Pure acetone is recovered in the acetone column as the top product. As an alternative, pure acetone may be separated as an upper side stream to allow removal of light-boilers at the top. Caustic soda is added to this column to convert aldehydes to high-boiling components.
The bottom product of this column, which is mainly water, is treated in the phenol removal unit to remove the organic components. It can also be recycled to the neutralization unit. The bottom product from the crude acetone column is sent to the first cumene column. The cumene with AMS and some phenol as well as water are separated as the top product. The water is separated in a decanter and treated in the phenol removal and in the water stripper to remove phenol, acetone, and cumene.
All process water is sent to the final treatment in a BWWT. The cumene is separated from low boilers, mainly acetone and water, in the second cumene column. The AMS is hydrogenated to cumene in the hydrogenation unit on selective palladium catalysts. These catalysts are highly selective toward the hydrogenation of AMS without any interfering hydrogenation of phenol.
Phenol is then separated from the cumene in a cumene scrubber, again using aqueous caustic soda as the extraction solvent.
The NaPh is routed to the neutralization unit. The cumene is recycled back to the oxidation unit. The bottom product from the first cumene column is sent to the tar column.
All high-boiling components are separated at the bottom. The tar is typically used as fuel to produce steam. Crude phenol is separated as the top product. As an alternative, crude phenol may be taken as an upper side stream to remove residual amounts of hydrocarbons at the top. Acidic ion exchange resins are used in fixed-bed reactors to accomplish conversion to high boilers [25]. These high-boilers are separated from pure phenol in the phenol column and routed 2 Phenols 19 to the tar column.
In the phenol column, pure phenol may be separated at an upper side stream to remove light-boilers at the top. Coal tar is a complex mixture of condensable organic components, emerging from coal carbonization [1]. These phenols are called tar acids.
The carbolic oil is treated with diluted caustic soda to extract the phenols as sodium phenolate salts. The aqueous phenolate solution is then treated with carbon dioxide to liberate the phenols from the salts.
This crude phenol fraction from carbolic oil consists of phenol, cresols, and xylenols. Phenol and o-cresol can be isolated by distillation. The separation of m- and p-cresol requires more effort due to the similar boiling points, see Table 2. Some methods are described in [1].
The xylenol isomers can be separated by combined distillation and extraction steps. Phenol, cresols, and xylenols are recovered from the aqueous phase by solvent extraction, for example with the Lurgi Phenosolvan process.
The phenols are produced and marketed by Merisol, a joint venture between Sasol and Merichem USA , with a total production of phenols phenol, cresols, xylenols of about , metric tons per year in [28].
Another large source is the recovery of phenols from the gasification process of lignite coal at Dakota Gasification Company USA. The annual production of phenol there is about 20, metric tons.
The total production in was around 8. Weber Table 2. Mixtures are called cresylic acids. More specifically, if they are recovered from coal tar, they are called tar acids. Cresols are monomethyl derivatives of phenol. Xylenols are dimethyl derivatives. Higher alkylphenols such as 4-tert-butylphenol, 4-iso-octylphenol, and 4-nonylphenol are used in phenolic resin production. Like phenol, o- and p-cresol are crystalline solids at room temperature while m-cresol is viscous oil.
Compared to phenol, they are less soluble in water. Like phenol, cresols can be recovered from coal tar and other natural sources, see Sects. Currently synthetic processes are an important route for the production of cresols.
The chlorination and sulfonation processes are similar to the former production routes to synthetic phenol. The synthesis via cymene hydroperoxide is also similar to the cumene-to-phenol process Hock process. But the process is more complex, due to the formation of all three cymene isomers. In addition some methyl groups are oxidized to primary peroxides and cause more costly distillation procedures.
Mainly m- and p-cresol are finally recovered from this process. Main product from the methylation of phenol is o-cresol. Besides the use for phenolic resins, other applications for cresols are the production of herbicides, fungicides, disinfectants, and plasticisers. They are all crystalline materials at room temperature. Compared to cresols, xylenols are less soluble in water, but can still be extracted from organic mixture with aqueous caustic soda. Xylenols can be recovered from the same natural sources as cresols and phenol.
Besides o-cresol, 2,6-Xylenol is the preferred product in the phenol methylation gas phase process [29] and the desired monomer for poly 2,6 dimethylphenylene oxide or PPO and used to make Noryl, a high performance thermoplastic resin. In the phenol methylation liquid phase process, mainly 2,4-xylenol besides 2,6xylenol is formed. There are similar routes for xylenols via chlorination and sulfonation as for cresols. Instead of toluene, xylenes are the precursors.
Finally, it is possible to produce 3,5-xylenol via alkylation of m-xylene, oxidizing to the corresponding peroxide and subsequent cleavage to 3,5-xylenol and acetone [30, 31]. Besides phenolic resins, other applications for xylenols are their use as solvents and disinfectants. Compared to phenol, it has significantly higher reaction rate toward formaldehyde. Resins from resorcinol and formaldehyde RF resins are mainly used in the rubber industry.
RF resins are used as adhesives for joining rubber with reinforcing materials, for example in tires and conveyer belts. Another important use is the high-quality wood adhesives. Special resins from resorcinol, phenol, and 22 M. Weber formaldehyde increase the curing rate in structural wood adhesives and allow cure at ambient temperatures.
Resorcinol is also used as a light stabilizer for plastics and for the production of sunscreen preparations for the skin ultraviolet absorbers. Resorcinol is produced via sulfonation of benzene to benzene The salt is dissolved in water and neutralized with sulphuric acid. Resorcinol is extracted with an organic solvent such as diisopropyl ether.
In the hydroperoxidation process, benzene and a recycled benzene—cumene mixture is alkylated with propylene to diisopropylbenzene isomers. The m-DiPB is then oxidized to m-diisopropylbenzene hydroperoxide. The peroxide is crystallized and dissolved in acetone. The handling of the solid organic peroxide requires special safety measures.
The cleavage is carried out under acidic conditions to convert the peroxide into resorcinol and acetone. Usually, sulphuric acid is used as the catalyst in a boiling acetone mixture. Presently the main use for BPA is the production of polycarbonates and epoxide resins. BPA is produced from phenol and acetone in the presence of an acidic ion exchange resin catalyst. Phenol is used in high molar excess.
After the reaction, light boilers like acetone and water are separated by distillation. Acetone is recycled to the reactor. BPA is then crystallized in phenol. After mechanical separation and washing of the crystals with phenol, molten BPA is further purified. Excess phenol from the crystallization and from distillation is recycled back to the reactor. References 1. Springer, Berlin 2. Pat , February 27, 3. Pat 2,, December 20, 5.
Pat 2,, September 11, 2 Phenols 23 6. American Chemical Society, Washington D. Techn, Heft 1, p 38 Hock H, Lang S Ber. Plenum Press, New York Weber M Chem. May , p Weber M Umweltpraxis, September , p 35 September , p 46 Techn, p Pat 6,, April 29, Gas production Accessed 15 January Chemical Week , July 23, Fiege H Cresols and Xylenols.
Pat 2,, November 27, Pat 2,, November 17, Over 30 million metric tons of formaldehyde represent the global worldwide consumption of formaldehyde for an array of products, besides phenolic resins. These include urea formaldehyde resins, melamine formaldehyde resins, polyacetal resins, methylenebis 4-phenyl isocyanate , butanediol, pentaerythritol, and others. The two basic processes to produce formaldehyde from methanol — the silver catalyst process and the metal oxide process — are described along with the strengths and weaknesses of the respective processes.
Furthermore, methanol plant siting location is a factor due to raw material natural gas and energy costs. The controversy regarding the classification of formaldehyde as a human carcinogen remains unsettled.
In , the International Agency for Research on Cancer IARC of the World Health Organization reclassified formaldehyde from a group 2A substance probable carcinogen to humans to a group 1 carcinogenic to humans substance. Yet no government regulating agency has classified formaldehyde as a known human carcinogen. The studies that acknowledged formaldehyde to be a human carcinogen are being re-analyzed with additional research by IARC to re-examine its current classification of formaldehyde.
By end of October , despite strong disagreement among participants of the voting body, who were evenly split at the vote, IARC concluded that there is sufficient evidence in humans of a causal association of formaldehyde with leukemia. Industry disagrees with this conclusion and believes that the weight of scientific evidence does not support such a determination. A review of all of these data is still in process but impact on possible governmental reclassifications expected to be seen in Kowatsch Introduction The public is accustomed to products that contain formaldehyde almost every day without any apparent awareness of the presence of formaldehyde in the product.
Various industries such as the residential construction industry, the automotive industry, the aircraft industry, and even the health care industry are just a few examples of its broad utility. Even more surprising and unknown to many persons is the fact that human bodies produce formaldehyde, and it occurs naturally in the air we breathe. Products that contain formaldehyde or materials made from formaldehyde enjoy a vital role in world economies, but their dependence on formaldehyde is largely invisible to the public.
Statistics are not always well designed to identify or quantify the value of formaldehyde to consumers or the contribution of the formaldehyde industry to the economy in terms of jobs, wages, and investment [1]. Special resins are made with other aldehydes, for example, acetaldehyde, butyraldehyde, furfural, glyoxal, or benzaldehyde, but these have not achieved much commercial importance. Ketones are also rarely used. Physical properties of some aldehydes [2—4] are compiled in Table 3.
Because of its variety of chemical reactions [5, 6] and relatively low cost basically reflecting the cost of methanol , it has become one of the most important industrial chemicals.
Formaldehyde is a hazardous chemical [7—11]. It causes eye, upper respiratory tract, and skin irritation. Significant eye, nose, and throat irritation does not generally occur until concentration levels of 1 ppm. Further information on toxicology and risk assessment of formaldehyde is mentioned in Sect. Physical properties are shown in Table 3.
It is highly reactive and commonly handled in aqueous solutions containing variable amounts of methanol where it forms predominantly adducts with the solvent [5, 6], that is, equilibrium mixtures of methylene glycol 3. Commercially formaldehyde is the most important aldehyde.
Other large applications include polyacetal resins, pentaerythritol, methylenebis 4-phenyl isocyanate MDI , 1,4 butanediol, and hexamethylenetetramine HMTA. Formaldehyde producers are primarily concerned with satisfying their own captive requirement for forward integrated products rather than supplying local merchant markets. However, there are some further aspects to consider, which strongly influence future demand and its impact on success in the market.
The availability and access to low-cost methanol feedstock is one of those aspects, followed by downstream integration into derivatives, and lastly, a continuous striving for sustainable developments in the wood panel industries. Any setbacks in economic developments that influence the growth in construction may result in further consolidations in the formaldehyde industry.
Besides raw material and energy costs, environmental regulations Kyoto protocol affect wood logging and the availability of raw wood resources. In some applications, formaldehyde-based wood adhesives are currently being substituted but this substitution is quite price-sensitive. Furthermore, discussions related to health problems caused by formaldehyde [20] even though scientific opinions are 34 S.
Kowatsch not consistent [21] are resulting in confusion amongst consumers, followed by erratic buying behavior. See Chap. In the developed world, growth in demand will typically track the gross domestic product, although it will be strongly correlated to the construction industry. In that sense, formaldehyde is an essential component used in the manufacture of numerous daily products such as automobile parts, computer chips, plywood, decorative surfaces, furniture, radio and TV sets, various sports equipment, and much more Fig.
As it was mentioned earlier, it is also used in the health care industry in prenatal diagnostics and in the preservation of vaccines. Cupboards and worktops veneering Cladding and interior ceilings Acoustic ceilings carpets, bitumen mats, shingles Insulation Cabinet doors Friction products, filters, tires, insulation and coating additives Sollits, lacia, trim Abrasive products Beams, structural beams, I-joists, tinger jointing Furniture plywood, chipboard, Parquet, laminate flooring lorm press, loil lamination Concrete forming Wall sheathing OSB Fig.
Table 3. UF resin is one of the mainstays in the building and construction industry. In these applications, it has a predominant market share. There are substitutes for each application but no substitute material has the broad range of properties of UF resins which consist of low cost, dimensional stability, hardness, clear glue line, and a fast curing process. Its combination of properties allows it to maintain a dominant market position in certain applications, such as high pressure laminates for exterior decorative surfaces, in spite of its higher cost.
Other resins, or different materials, may be substituted for MF resin-based products, but are more costly and less appealing to the consumer. PF resin is another important product for the building and construction industry. Other important end uses include automobile applications e. Like UF resins, it has a predominant market share in its major applications.
There are substitutes for each application but no substitute material has the broad range of properties of PF resins where high strength, dimensional stability, the ability to 36 S. Kowatsch resist water, and thermal stability are required. In addition, current production methods are designed and integrated for the continuing use of PF resins. Some formaldehyde is used in the preparation of MDI. The majority of MDI is used in the manufacture of rigid polyurethane foams. These products are commonly used in construction applications for their superior insulating and mechanical properties.
Tensile strength, hardness, bending strength, compression strength and water absorption are determined and compared to the properties of hardened gypsum without any admixtures. Experimental The specimens of unmodified and modified gypsum with resole resin were prepared with hydration of calcium sulfate hemihydrate.
The resole-gypsum ratio was varied from 2. Resole resin Preparation of Resole -Phenol Formaldehyde Resin Resin was prepared by condensation reaction between phenol and formaldehyde under alkaline conditions.
In a ml three-necked round bottom flask fitted with condenser, mechanical stirrer and thermometer, 0.
Two layers were formed then we separate the aqueous layer from resole by decantation[12]. Gypsum Gypsum used as a main matrix in this project was calcium sulfate hemihydrate gypsum CaSO4.
In charpy method for impact measurement the specimen is notched sometime un-notched [13,14]. In this method, a free swinging pendulum with a round-up mount is used as an impactor.
The Charpy impact strength of un-notched specimens G in kilo joules per square meter is given by [13]: Where U is impact energy in Jules, absorbed by the test specimen, X is the width of specimen in mm and Y is the thickness in mm of the test specimen. The samples were prepared according to ISO Bending Strength Bending strength can be defined as the resistance of material to bending or the ultimate load to be tolerated by the specimen without failure.
From three-point test, modulus of elasticity E can be evaluated [16]. Where M is the load applied at the specimen in gram. S the bending of specimen. I is the engineering bending moment. Which can be determined by the following relation: Where b is the width of specimen d is the thickness of specimen Compression Strength Compression test or crushing strength is the maximum stress that a rigid material withstand under longitudinal compression.
Compression strength is the measured as a force per unit area of initial cross-section 50mm , and is listed as MPa. When the resin matrix has a high cross-link density, the polymer becomes rigid with a high value of compressive strength [17]. Modulus of Elasticity Three point flexural test was used to evaluate the elastic bending modulus of samples E.
The mechanical tests were determined by using the following relation [18]. Where g is 9. Swelling test The gypsum specimens were dried to constant weight and immersed in deionized water at room temperature. The gypsum specimens were periodically weighted after removing excess water from the surface of samples with a filter paper.
Swelling was calculated from the following relation: Where, Wt is the weight of swollen gypsum specimen at time t and Wo is the initial weight of dry specimen. The swelling of unmodified gypsum and gypsum-Resole composite were done through the immersion of these materials in water for different time intervals from 15 to minutes. Table 1 and fig. The decreases in water absorption with increase of percentage of Resole polymer may be attributed to the decrease in porosity of gypsum structure.
Inherently, the solid structure of solidified gypsum, which, created by hydration of hemihydrated gypsum is porous and the porosity increases with increase in water:gypsum ratio[19]. Table 1 : Degree of swelling for Phenolic resin Resole 0 15 30 45 60 75 90 12 16 Sample mi mi mi mi mi mi mi min 0m min mi 5m min min n n n n n n n in n in 2. It was found that the impact strength is increased when, the Resole resin proportion in gypsum-Resole composite increases figure3 table2.
It is clear from table2, that the impact strength increases from This increase in impact strength of the composite might be attributed to the ability of the Resole polymer to fillin the voids in the plaster and gives an elastic behavior to the gypsum-Resole composite, whichfinally lead to increase the impact strength of gypsum-Resole composite.
By providing the knowledge necessary for selecting a fabrication process, thermoset material and methods for determining the all important cost of thermoset parts this new edition is an invaluable decision-making aid and reference work for practitioners in a field with growing importance.
Combining materials data, information on processing techniques, and economic aspects, Biron provides a unique end-to-end approach to the selection and use of materials in the plastics industry and related sectors New material on bio-sourced thermosets, natural fibers, and recycling of thermosets Concise and easy-to-use source of information and decision-making aid.
The second edition of this classic text book has been completely revised, updated, and extended to include chapters on biomimetic amination reactions, Wacker oxidation, and useful domino reactions.
The first-class author team with long-standing experience in practical courses on organic chemistry covers a multitude of preparative procedures of reaction types and compound classes indispensable in modern organic synthesis.
Throughout, the experiments are accompanied by the theoretical and mechanistic fundamentals, while the clearly structured sub-chapters provide concise background information, retrosynthetic analysis, information on isolation and purification, analytical data as well as current literature citations. Finally, in each case the synthesis is labeled with one of three levels of difficulty. An indispensable manual for students and lecturers in chemistry, organic chemists, as well as lab technicians and chemists in the pharmaceutical and agrochemical industries.
Written by leading experts in the field, and covering composite materials developed from different natural fibers and their hybridization with synthetic fibers, the book's chapters provide cutting-edge, up-to-date research on the characterization, analysis and modelling of composite materials.
Contains contributions from leading experts in the field Discusses recent progress on failure analysis, SHM, durability, life prediction and the modelling of damage in natural fiber-based composite materials Covers experimental, analytical and numerical analysis Provides detailed and comprehensive information on mechanical properties, testing methods and modelling techniques. Handbook of Thermoset Plastics, Fourth Edition provides complete coverage of the chemical processes, manufacturing techniques and design properties of each polymer, along with its applications.
This new edition has been expanded to include the latest developments in the field, with new chapters on radiation curing, biological adhesives, vitrimers, and 3D printing. This detailed handbook considers the practical implications of using thermoset plastics and the relationships between processing, properties and applications, as well as analyzing the strengths and weakness of different methods and applications. The information included will also be of interest to researchers and advanced students in plastics engineering, polymer chemistry, adhesives and coatings.
Offers a systematic approach, guiding the reader through chemistry, processing methods, properties and applications of thermosetting polymers Includes thorough updates that discuss current practice and the new developments on biopolymers, nanotechnology, 3D printing, radiation curing and biological adhesives Uses case studies to demonstrate how particular properties make different polymers suitable for different applications Covers end-use and safety considerations.
The combination of functional polymers with inorganic nanostructured compounds has become a major area of research and technological development owing to the remarkable properties and multifunctionalities deriving from their nano and hybrid structures. In this context, polyhedral oligomeric silsesquioxanes POSSs have increasing importance and a dominant position with respect to the reinforcement of polymeric materials.
Although POSSs were first described in by Scott, these materials, however, have not immediately been successful if we consider that, starting from and up to , we find in the literature 85 manuscripts regarding POSSs; which means that less than two papers per year were published over 50 years.
Since , we observe an exponential growth of scientific manuscripts concerning POSSs. The introduction of POSSs inorganic nanostructures into polymers gives rise to polymer nanostructured materials PNMs with interesting mechanical and physical properties, thus representing a radical alternative to the traditional filled polymers or polymer compositions. Skip to content. Phthalonitrile Resins and Composites. Phthalonitrile Resins and Composites Book Review:. Fire Performance of Phthalonitrile Resins Composites.
Author : S. High Performance Phthalonitrile Resins. Thermosets Book Review:. Phenolic Resins A Century of Progress. Advanced and Emerging Polybenzoxazine Science and Technology. Polymer Processing and Characterization. Polymer Processing and Characterization Book Review:. Composite Materials. Author : Kamal K. Composite Materials Book Review:.
Structural Materials and Processes in Transportation. Manufacturing Processes for Advanced Composites.
0コメント