Alkyd polyester thermosetting polymers

This is a very broad class of compounds commonly used in coatings. Over 400-500 different alkyd resins are commercially available. They are polyesters containing unsaturation that can be cross-linked in the presence of an initiator known traditionally as a drier. A common example is the alkyd formed from phthalic anhydride and a glyceride of linolenic acid obtained from various plants. Cross-linking of the multiple bonds in the long unsaturated chain R produces the thermoset polymer by linking R groups of separate molecules with each other. 

In this book I have confined discussion to those polymeric materials which are cured by chemical reaction and which have found widespread application in the construction industry. As such, the book covers materials based on epoxies, polyurethanes, silicones, polysulphides, alkyds and polyesters. In addition, there is a chapter on hybrid polymer systems and one on acrylics. It is true that acrylic emulsions are not strictly thermosetting polymer systems, but their widespread use and importance made their exclusion difficult. These materials find use as coatings, sealants, adhesives, grouts, flooring compounds, repair compounds and waterproofing agents. 

Phthalide (241) has been used as an additive used to prepare polyesters with low molten viscosity <91JAP(K)03200859>. Phthalic anhydride (242), prepared by the oxidation of o-xylene, is of major importance to the chemical industry with 1992 production over 400000 tonnes <93CEN38>. It is used as a monomer in the preparation of alkyd resins (a polyester with glycerol and other polyols) and thermosetting polymers (with maleic anhydride and polyols). Another important application is in the production of dioctyl phthalate (243), which is used as a plasticizer for PVC (1991 production, 123000 tonnes). Over 400 references pertaining to the use of phthalic anhydride in polymer compositions have appeared since 1982. Tetrabromophthalic anhydride (244) has been used to prepare flame-retardant bisphthalimides as polymer additives <90JAP(K)02145568>. 

The unsaturated polyesters (mainly used for coatings, including alkyds) are probably better known. However this type of polyester will be discussed later together with other thermosetting polymers. 

The condensation reaction between carboxylic acid and alcohol to form an ester and water is a fundamental chemical reaction, and has been known at least from when the term organic chemistry was coined in the early nineteenth century. From the mid- to late-nineteenth century, studies were carried out on the reactions of compounds containing more than one acid group with compounds containing more than one hydroxyl group. These studies produced the first polyester resins, and lead to the development in the early twentieth century of various thermoset polymers such as the alkyd resins. 

Injection molding ABS, acetal, acrylic, alkyd, allyl, amino, cellulosics, epoxy fluorocarbons, liquid crystal polymer, nylon, phenolic, polycarbonate, polyester (thermoplastic), polyester (thermoset), polyethylene, polyphenylene oxide, polypropylene, polystyrene, polysulfone, polyurethane (thermoplastic), PVC, SAN... 

Thermoset materials are produced by the direct formation of network polymers from monomers, or by crosslinking linear prepolymers. Important thermosets include alkyds, amino and phenolic resins, epoxies, unsaturated polyesters and polyurethanes. Thermosetting polymers consist of two liquid components, one containing a resin and the other a hardener [1]. 

Phenolic, epoxy, urea, melamine, and polyester (alkyd) polymers are cross-linked (thermoset) plastics. They are solvent-resistant and are not softened by heat. Unlike the thermoplastic step reaction polymers, which are produced by the condensation of two difunctional reactants, these network polymers are produced from reactants at least one of which has a degree of functionality higher than two. 

Adipic acid [124-04-9] - [ALKYD RESINS] (Vol 2) - [DICARBOXYLIC ACIDS] (Vol 8) - [FOOD ADDITIVES] (Vol 11) - (ELECTROCHEMICALPROCESSDTG - ORGANIC] (Vol 9) -barrier polymers from [BARRIERPOLYMERS] (Vol 3) -from cyclohexane [HYDROCARBONS - C1-C6] (Vol 13) -from cyclohexane [HYDROCARBON OXIDATION] (Vol 13) -from cyclohexanol [CYCLOHEXANOL AND CYCLOHEXANONE] (Vol 7) -as food additive [FOOD ADDITIVES] (Vol 11) -nylon from [POLYAMIDES - FIBERS] (Vol 19) -nylon-6,6 from [POLYAMIDES - GENERAL] (Vol 19) -nylon-6,6 from [POLYAMIDES - PLASTICS] (Vol 19) -m polyester production [COMPOSITE MATERIALS - POLYMER-MATRIX - THERMOSETS] (Vol 7) -m polyester resins [POLYESTERS, UNSATURATED] (Vol 19) -soda preservatives [CARBONATED BEVERAGES] (Vol 5)... 

Thermoset resins covers an extremely wide range, including phenol formaldehyde polymers, aminopolymers, PUs, epoxies, and thermoset polyesters, which include the alkyd and unsaturated vinyl ester resins. Of special interest at the present time are those that comprise the resin component of liber-reinforced composites that are finding increasing use in commercial and defense sectors, where fire resistance is of paramount importance. Typical resins used are those listed in Table 2.4 along with typical, respective LOI values in descending order of increased inherent fire resistance. 

Consider the simple alkyd recipe shown in Table 5-1, part (i). Alkyds are polyesters produced from polyhydric alcohols and polybasic and monobasic acids. They are used primarily in surface coatings. The ingredients of these polymers contain polyfunctional monomers and it is possible that such polymerizations could produce a thermoset material during the actual alkyd synthesis. This is of course an unwanted outcome, and calculations based on the Carothers equation can be used to adjust the polymerization recipe to produce a finite molecular weight polymer in good yield. The recipe can also be adjusted to provide other desirable characteristics of the product, such as an absence of free acid groups which may react adversely with some pigments. 

Very little is known about the structure of the cured polyester resin. The products definitely belong in the thermoset class. There is some correlation between maximum physical properties a nd a molar ratio of 1 1 between double bonds in the alkyd and monomer. However, this is not critical and simple cross-linking does not tell the full story. The styrene monomer can be present in twice the molar amount needed, and yet complete copolymerization takes place without apparent formation of styrene polymer. 

Thermoset, those that cannot be resoftened, including polyethylene (crosslinked), phenolics, and alkyds like the polyesters (polymers based on maleic, terephthalic, or other carboxylic acids and glycol, propylene glycol or similar alcohols). 

Thermo set polymers Alkyd resins Amino resins Epoxy resins Phenolic resins Poly(bis maleimide) Polyesters, unsaturated Thermoset resin Tohprene TOR Torelina Torlon TP 301 TPX... 

Polyesters A broad class of polymers usually made by condensation of a diol with dicarboxylic acid or anhydride. Polyesters consist of chains with repeating carbonyloxy group and can be aliphatic or aromatic. There are thermosetting polyesters, such as alkyd resins and unsaturated polyesters, and thermoplastic polyesters such as PET. The properties, processing methods, and applications of polyesters vary widely. Also called Polyester Resins. 

Chem. Descrip. 2-Flydroxy-4-n-octyloxybenzophenone CAS 1843-05-6 EINECS/ELINCS 217-421-2 Uses Lt. stabilizer, UV absorber for polymers incl. acetals, acrylics, ABS, alkyds, cellulosics, epoxies, PC, thermoplastic and thermoset polyester, polyethylene, PP, PS, SAN, and surface coatings UV absorber for PVC flexible and semirigid applies, such as automotive body side molding, automotive surface coatings costabilizer for polyethylene film in agric. or greenhouse applies. 

Thermosets are based on crosslinked polymers. They harden permanently with the aid of catalysts and/or heat, and cannot be remelted without degrading their polymeric structure. The thermosetting family includes phenolics, epoxides, alkyds, polyurethanes, melamine, urea-formaldehyde and unsaturated polyesters. 

Unsaturated low molecular weight (M between 1000 and 10000), often branched, used as macromonomers for synthesis of thermosets (polyester resins), or thermosetting materials by themselves (alkyd resins). They are prepared from several monomers, namely phthalic and maleic anhydrides, adipic acid, iso-phthalic acid, natural fatty acids or triglycerides, and a great variety of multifunctional alcohols. In a few special cases, they may be saturated and/or linear for use as macromonomers in the production of polyurethanes or other polymers. 

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