Unsaturated polyesters/natural rubber

In India, flexible sheet explosives are generally made from indigenously available unsaturated polyester resins, epoxy resins and natural rubber etc. and common... 

Isophorone [14.268], [14.269] is an unsaturated cyclic ketone. It consists of a-isophorone [78-59-1] (3,5,5-trimethyl-2-cyclohexen-l-one), which contains about 1-3% of the isomer P-isophorone [471-01-2] (3,5,5-trimethyl-3-cyclohexen-l-one). Isophorone is a stable, water-white liquid with a mild odor that is miscible in all proportions with organic solvents. It dissolves many natural and synthetic resins and polymers, such as poly(vinyl chloride) and vinyl chloride copolymers, poly(vinyI acetate), polyacrylates, polymethacrylates, polystyrene, chlorinated rubber, alkyd resins, saturated and unsaturated polyesters, epoxy resins, cellulose nitrate, cellulose ethers and esters, damar resin (dewaxed), kauri, waxes, fats, oils, phenol-, melamine-, and urea-formaldehyde resins, as well as plant protection agents. However, isophorone does not dissolve polyethylene, polypropylene, polyamides. 

E/TFE = ethylene/tetrafluoroethylene, E/CTFE = ethylene/chlorotrifluoroethylene, EPE = oxide, E/VAL = ethylene/vinyl alcohol, FEP = tetrafluoroethylene/hexafluoropropylene, FU = furan, pA = polyamide, PCTFE = polychlorotrifluoroethyl-ene, HDPE = high-density polyethylene, PF = propylene formaldehyde, PFA = perfluoro alkoxyalkane, PP = polypropylene, PTFE = polytetrafluoroethylene, PUR = polyurethane, PVC = polyvinyl chloride, PVDF = polyvinylidene fluoride, UP = unsaturated polyester, UP-GF = fiberglass-reinforced unsaturated polyester, VE-GF = fiberglass-reinforced vinyl ester, FU-GF = fiberglass-reinforced furane, EP-GF = fiberglass-reinforced ester, CR = chloroprene rubber, CSM = chlo-rosulfonyl polyethylene, FPM = vinylidene fluoride/hexafluoropropylene copolymer, HR = isobutane-isoprene rubber, NBR = nitrile-butadiene rubber, NR = natural rubber, SBR = styrene-butadiene rubber. 

Cross-linking by addition polymerization is also used to a considerable extent. Unsaturated polyesters are cross-linked by copolymerization with styrene or methyl methacrylate. Cross-linking soft, natural rubber with sulfur gives the normally used hard, vulcanized rubber. Ethylene-propylene rubbers can be cross-linked with peroxides. The cross-linking of elastomers is also called vulcanization, since the classic cross-linking of natural rubber, cis-l,4-poly(isoprene), uses heat and sulfur, which were the elements assigned to the god Vulcan (see also Chapter 37). 

Chlorinated paraffin (chlorocosane) n. Any of a family of yellow to light amber liquids produced by chlorinating a paraffin oil, with uses as secondary plasticizers for vinyls, polystyrene, polymethyl methacrylate, and coumarone-indene resins. Chlorinated paraffins also impart flame resistance to polyolefins, polystyrene, PVC, natural rubber, and unsaturated polyester resins. 

This technique has found the following applications in addition to those discussed in Sections 10.1 (resin cure studies on phenol urethane compositions) [65], 12.2 (photopolymer studies [66-68]), and 13.3 (phase transitions in PE) [66], Chapter 15 (viscoelastic and rheological properties), and Section 16.4 (heat deflection temperatures) epoxy resin-amine system [67], cured acrylate-terminated unsaturated copolymers [68], PE and PP foam [69], ethylene-propylene-diene terpolymers [70], natural rubbers [71, 72], polyester-based clear coat resins [73], polyvinyl esters and unsaturated polyester resins [74], polyimide-clay nanocomposites [75], polyether sulfone-styrene-acrylonitrile, PS-polymethyl methacrylate (PMMA) blends and PS-polytetrafluoroethylene PMMA copolymers [76], cyanate ester resin-carbon fibre composites [77], polycyanate epoxy resins [78], and styrenic copolymers [79]. 

Natural rubber/polylactide Natural rubber/unsaturated polyester resin Natural rubber or maleated natural rubber/ethylene vinyl acetate... 

The crosslinking process consists of forming covalent bonds, either between small molecules, such as phenol and formaldehyde, or between existing linear macromolecules, as in the case of unsaturated polyesters or epoxy resins. The process of crosslinking existing linear macromolecules is analogous to the vulcanization of natural rubber. 

Other plastics that are resistant to PEGs even at elevated temperatures are polypropylene, polystyrene, articles made from natural rubber, polytetrafluoroeth-ylene, polyoxymethylene, and unsaturated polyester resins. 

Crosslinked (insoluble and infusible) phenol- and resorcinol-formaldehyde, urea- and melamine-formaldehyde, epoxies, polyurethanes, natural and synthetic rubbers if vulcanized, anaerobics, and unsaturated polyesters. 

These are chemicals whose function is to produce a crosslinked, thermosetting plastic from an initially linear or branched polymer. For example, a vinyl monomer, such as styrene, a free-radical initiator, and sometimes a promoter (e.g., cobalt naphthenate, to speed up the reaction) can be dissolved in a low molecular weight unsaturated polyester resin, which forms crosslinks by an ordinary addition mechanism involving the double bonds in the polyester (Example mprb2.3). Curing is also important in forming tires, as sulfur is compounded with natural, butadiene, or isoprene mbber to form a crosslinked rubber. 

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