Unsaturated Polyester-Styrene Compositions

An unsaturated polyester dissolved in polymerizing styrene forms an AB crosslinked polymer network. When combined with another thermosetting resin, an IPN, or more usually, an SIN, is formed. 

Useful for solid dielectric and protective coatings for electrical apparatus is a polyester-styrene/epoxy-chlorinated anhydride composition. 

The chlorinated anhydride is prepared by reacting chlorendic anhydride (hexachloroendomethylenetetrahydrophthalic anhydride) with glycerol. The chlorine groups impart flame resistance. 

Unsaturated polyester-styrene compositions were mixed with castor oil and TDI to form a polyurethane network (Example 6). Such compositions make electrical ballasts with excellent heat dissipation and also reduce 

Novel adhesives and casting resins have been made by the use of 

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Arc resistance and electrical insulation, combined with low volatility, are mentioned for polyester-styrene polymers containing cured aminoplasts as fillers. Curable epoxy resins may replace the polyester-styrene compositions. Reinforced unsaturated polyester-styrene compositions with or other thermoplastic vinyl halide form a... 

Ketone Peroxides. These materials are mixtures of compounds with hydroperoxy groups and are composed primarily of the two stmctures shown in Table 2. Ketone peroxides are marketed as solutions in inert solvents such as dimethyl phthalate. They are primarily employed in room-temperature-initiated curing of unsaturated polyester resin compositions (usually containing styrene monomer) using transition-metal promoters such as cobalt naphthenate. Ketone peroxides contain the hydroperoxy (—OOH) group and thus are susceptible to the same ha2ards as hydroperoxides. 

Bisphenols is a broad term that includes many chemicals with the common chemical structure of two phenolic rings joined together by a bridging carbon. Bisphenol A is a monomer widely used in the manufacture of epoxy and phenolic resins, polycarbonates, polyacrylates and corrosion-resistant unsaturated polyester-styrene resins. It can be found in a diverse range of products, including the interior coatings of food cans and filters, water containers, dental composites and sealants. [4]. BPA and BP-5 were selected for testing by the whole... 

Let us consider the variation of the composition in a two-component system (R + H), e.g., unsaturated polyester-styrene or epoxide-amine. Are density measurements capable of detecting such a variation ... 

Among the emerging pollutants of industrial origin, Bisphenol A [2,2 bis(4-hydroxydiphenyl)pro-pane] (BPA) has special relevance since it was one of the first chemicals discovered to mimic estrogens as endocrine disrupters.147 This compound was first reported by Dianin in 1891.1411 BPA is produced in large quantities worldwide, mainly for the preparation of polycarbonates, epoxy resins, and unsaturated polyester-styrene resins.149 The final products are used in many ways, such as coatings on cans, powder paints, additives in thermal paper, in dental composite fillings, and even as antioxidants in plasticizers or polymerization inhibitors in polyvinyl chloride (PVC). To a minor extent, BPA is also used as precursor for flame retardants such as tetrabromobisphenol A or tetrabromobisphenol-S-bis(2,3-dibromopropyl) ether.150 This substance can enter the environment... 

Uses Med.-temp. initiator for polymerization of vinyl monomers and the curing of styrene-unsaturated polyester resin compositions crosslinking agent for unsat. polyesters catalyst in premix polyester BMC, SMC Manuf./Distiib. Akzo Nobel http //www.akzonobel.com] Atofina http //www.atofinachemicals.com] Aztec Peroxides Norac http //www.norac.com Trade Name Synonyms Aztec TBPEH t[Aztec Peroxides] Aztec TBPEH-30-AL t[Aztec Peroxides] Esperox 28 [Crompton/Olefins Styrenics] Luperox 26 [Atofina SA http //www.atofina.com] Atofina http //www.atofinachemicals.com]] Perbutyl O t[NOF http //www.nof.co.jp]... 

The incorporation of sisal fibres into composites containing wood particles has also attracted some attention [45]. This system involved an unsaturated polyester/styrene matrix and pine wood flour. A composite with 12 per cent (v/v) of wood particles displayed a 10-fold increase in the work of fracture upon the addition of 7 per cent (v/v) of sisal fibres. 

Technique, J. Dental Res. 53(3), 1074 (1974). IPNs as denture-base materials. Celanese Coatings Company, Resin Compositions, Br. Pat. 1,205,682 (1970). Unsaturated polyester-styrene/epoxy SIN. 

V. F. G. Cooke and D. H. Thorpe, Additive for Low Profile Polymerizable Unsaturated Polyester Molding Composition, U.S. Pat. 4,125,702 (1978). Lightly crosslinked poly(vinyl chloride)-suspension-sized particles dispersed in unsaturated polyester-styrene. 

Westinghouse Electric International Co., Improvements in or Relating to Resinous Compositions, Br. Pat. 794,541 (1958). Unsaturated polyester-styrene/epoxy SINs. Low-shrinkage resins. 

The macroscopic composites are those in which one or both phases tend to have structures large enough to be easily seen with the naked eye. These include paint hlms (paint itself is usually a particulate composite), adhesive joints, and foams (e.g., the familiar polystyrene foams used for coffee cups because of their low heat transfer coefficient). The fabric laminates alternate layers of inorganic cloth and plastic. An important subclass usually has multiple layers of glass cloth or chopped fiber interspersed with layers of unsaturated polyester-styrene AB-cross-linked materials see Section 2.7.3. These sheet molding compounds are widely used for the hulls of pleasure boats, because they are light weight and very puncture resistant, as well as for automotive bodies see Section 13.9.1. 

The second largest use at 21% is for unsaturated polyester resins, which are the products of polycondensation reactions between molar equivalents of certain dicarboxyhc acids or thek anhydrides and glycols. One component, usually the diacid or anhydride, must be unsaturated. A vinyl monomer, usually styrene, is a diluent which later serves to fully cross-link the unsaturated portion of the polycondensate when a catalyst, usually a peroxide, is added. The diacids or anhydrides are usually phthahc anhydride, isophthahc acid, and maleic anhydride. Maleic anhydride provides the unsaturated bonds. The exact composition is adjusted to obtain the requked performance. Resins based on phthahc anhydride are used in boat hulls, tubs and spas, constmction, and synthetic marble surfaces. In most cases, the resins contain mineral or glass fibers that provide the requked stmctural strength. The market for the resins tends to be cychcal because products made from them sell far better in good economic times (see Polyesters,unsaturated). 

Commonly used monomers for UV curing include acrylates (7), styrene/unsaturated polyesters (8,9), and thiol-ene compositions (10-12). Currently, acrylate-functional systems constitute a major share of the UV curable polymers market, mainly due to their rapid curing via free radical chain polymerization. 

Thermoset plastics have also been pyrolysed with a view to obtain chemicals for recycling into the petrochemical industry. Pyrolysis of a polyester/styrene copolymer resin composite produced a wax which consisted of 96 wt% of phthalic anhydride and an oil composed of 26 wt% styrene. The phthalic anhydride is used as a modifying agent in polyester resin manufacture and can also be used as a cross-linking agent for epoxy resins. Phthalic anhydride is a characteristic early degradation product of unsaturated thermoset polyesters derived from orf/io-phthalic acid [56, 57]. Kaminsky et al. [9] investigated the pyrolysis of polyester at 768°C in a fiuidized-bed reactor and reported 18.1 wt% conversion to benzene. 

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