Polyepichlorohydrin copolymers

Polyepichlorohydrin copolymer or terpolymer compounds can provide vibration dampening comparable to natural rubber (NR), but at an extended temperature range. This characteristic makes polyepichlorohydrin compounds a good choice for suspension mounts and impact absorbers, which must operate at higher temperatures than practical for natural rubber. Typical data are shown in Figures 7.3 and 7.4. 

In 1957, it was discovered that organometaUic catalysts gave high mol wt polymers from epoxides (3). The commercially important, largely amorphous polyether elastomers developed as a result of this early work are polyepichlorohydrin (ECH) (4,5), ECH—ethylene oxide (EO) copolymer (6), ECH—aUyl glycidyl ether (AGE) copolymer (7,8), ECH—EO—AGE terpolymer (8), ECH—propylene oxide (PO)—AGE terpolymer (8,9), and PO—AGE copolymer (10,11). The American Society for Testing and Materials (ASTM) has designated these polymers as follows ... 

Epichlorohydrin Elastomers without AGE. ECH homopolymer, polyepichlorohydrin [24969-06-0] (1), and ECH—EO copolymer, poly(epichlorohydrin- (9-ethylene oxide) [24969-10-6] (2), are linear and amorphous. Because it is unsymmetrical, ECH monomer can polymerize in the head-to-head, tail-to-tail, or head-to-tail fashion. The commercial polymer is 97—99% head-to-tail, and has been shown to be stereorandom and atactic (15—17). Only low degrees of crystallinity are present in commercial ECH homopolymers the amorphous product is preferred. 

Vulcanisation can be effected by diamines, polyamines and lead compounds such as lead oxides and basic lead phosphite. The homopolymer vulcanisate is similar to butyl rubber in such characteristics as low air permeability, low resilience, excellent ozone resistance, good heat resistance and good weathering resistance. In addition the polyepichlorohydrins have good flame resistance. The copolymers have more resilience and lower brittle points but air impermeability and oil resistance are not so good. The inclusion of allyl glycidyl ether in the polymerisation recipe produces a sulphur-curable elastomer primarily of interest because of its better resistance to sour gas than conventional epichlorhydrin rubbers. 

GAP is synthesized by replacing C-Cl bonds of polyepichlorohydrin with C-N3 bonds.The three nitrogen atoms of the N3 moiety are attached linearly with ionic and covalent bonds in every GAP monomer unit, as shown in Fig. 4.6. The bond energy of N3 is reported to be 378 kj mol per azide group. Since GAP is a liquid at room temperature, it is polymerized by allowing the terminal -OH groups to react with hexamethylene diisocyanate (HMDl) so as to formulate GAP copolymer, as shown in Fig. 4.7, and crosslinked with trimethylolpropane (TMP) as shown in Fig. 4.8. The physicochemical properhes of GAP prepolymer and GAP copolymer are shown in Table 4.4 and Table 4.5, respectively.I ]... 

Polyepichlorohydrin and copolymers and terpolymers of epichlorohydrin with ethylene oxide and allyl glycidyl ether are useful elastomers [Body and Kyllinstad, 1986]. 

VC/Polyepichlorohydrin and VC/Poly (epichlorohydrin-co-ethylene oxide) Graft Copolymers. Graft copolymers of this type with high backbone-polymer content should be useful PVC additives. 

VC/Polyepichlorohydrin and VC/Poly(epichlorohydrin-co-ethylene oxide) Graft Copolymers. Alloys of PVC and graft copolymers of this type with high backbone-polymer content give interesting results in the field of bottle blowing (12). The combination of transparency and impact strength that can be realized with these compositions should enable them to penetrate into the field covered at present by PVC-MBS mixtures. 

FIGURE 9.17 Dependence of productivity and separation factor /3p C6H5CH3/H2O of membranes based on various rubbery polymers on the glass transition temperature of the polymer (pervaporation separation of saturated toluene/water mixture, T = 308 K) (1) polydimethyl siloxane (2) polybutadiene (3) polyoctylmethyl siloxane (4) nitrile butadiene rubber with 18% mol of nitrile groups (5) the same, 28% mol of nitrile groups (6) the same, 38% mol of nitrile groups (7) ethylene/propylene copolymer (8) polyepichlorohydrin (9) polychloroprene (10) pol3furethane (11) polyacrylate rubber (12) fluorocarbon elastomer. (From analysis of data presented in Semenova, S.I., J. Membr. Sci., 231, 189, 2004. With permission.)... 

A number of chlorinated poly(ethers) have practical uses. A common compound from this group is polyepichlorohydrin, [-CH(CH2CI)CH20-]n. Polyepichlorohydrin has practical applications as an elastomer and is used in copolymers with propylene oxide, ethylene oxide, allyl glycidyl ether (1-allyloxy-2,3-epoxypropane), etc. Another example is poly oxy[2,2 -bis(chloromethyl)-1,3-propandiyl] or poly[oxy-1,3-(2,2 -dichloromethyl)propylene], CAS 25323-58-4, which can be used as inert lining material for chemical plant equipment, as adhesive, coating material, etc. This macromolecule can be prepared starting with pentaerythritol in the sequence of reactions shown below ... 

Graft copolymers of ethyleneimine on polyepichlorohydrine or polystyrene chelated with heavy metal ions like Hg2 , Cu2 and Cd2 + may have possibility in ion-exchange membranes for the transport of ions 31). 

It should be noted that SC copolymers based on nonmesogenic SCs and NLO mes-ogenic SCs offer the opportunity to fine-tune the polymer properties by varying the ratio of the NLO mesogenic SCs, although care must be taken to characterize the product, since the final ratios of the SCs may not correspond to the feed concentrations. An interesting example is the series of copolyethers prepared by chemical modification of atactic polyepichlorohydrin with the sodium salt of 4-cyano-4 hydroxybiphenyl [188, 207] (45). 

Polymer Testing 19, No.4, 2000, p.415-7 CHARACTERIZATION OF POLYEPICHLOROHYDRIN AND COPOLYMERS OF EPICHLOROHYDRIN-GYLICIDYL ETHERS BY IR SPECTROSCOPY Glavcheev I Sirashki G Mateva R Sofia,University of Chemical Technology ... 

Most compounders use a combination of physical and chemical antiozonants and achieve excellent protection in this way. For more severe ozone-resistance problems, there are, of course, a number of specialty elastomers that are saturated and therefore completely ozone-resistant ethylene/propylene rubber, chlorinated and chlorosulfonated polyethylene, ethylene/vinyl acetate, ethylene/acrylic esters, butyl rubber, SEES, plasticized PVC, butyl acrylate copolymers, polyepichlorohydrin and copolymers, polyetherester block copolymer, polyurethane, and silicone. 

Figure 1 Polymer interpretation chart. PAI, polyamideimide PC, polycarbonate UP, unsaturated polyester PDAP, diarylate phtalate resin VC-VAc, vinyl chloride-vinyl acetate copolymer PVAc, polyvinyl acetate PVFM, polyvinyl formal PUR, polyurethane PA, polyamide PMA, methacrylate ester polymer EVA, ethylene-vinyl acetate copolymer PF, phenol resin EP, epoxide resin PS, polystyrene ABS, acrylonitrile-butadiene-styrene copolymer PPO, polyphenylene oxide P-SULFONE, poly-sulfone PA, polyamide UF, urea resin CN, nitrocellulose PVA, polyvinyl acetate MC, methyl cellulose MF, melamine resin PAN, polyacrylonitrile PVC, polyvinyl chloride PVF, polyvinyl fluoride CR, polychloroprene CHR, polyepichlorohydrin SI, polymethylsiloxane POM, polyoxy-methylene PTFE, polytetrafluoroethylene MOD-PP, modified PP EPT, ethylene-propylene terpolymer EPR, ethylene-propylene rubber PI, polyisoprene BR, butyl rubber PMP, poly(4-methyl pentene-1) PE, poly(ethylene) PB, poly(butene-l). (Adapted from Ref. 22, p. 50.)...

Synthetic rubbers are produced as commodities. Polybutadiene, polybutylene, polychloroprene and polyepichlorohydrin are examples of elastomeric homopolymers. Copolymeric rubbers comprise poly-(butadiene-co-styrene), poly(butadiene-co-acryloni-trile), poly(ethylene-co-propylene-co-diene), and poly-(epichlorohydrin-co-ethylene oxide). The unsaturated group in the comonomer provides reactive sites for the crosslinking reactions. Copolymers combine resilience with resistance to chemical attack, or resilience in a larger temperature range, and thermoplastic-like properties. There are several studies in the literature describing the preparation of blends and composites of elastomers and conductive polymers. A description of some significant examples is given in this section. 

Although not strictly the subject matter of this book, work is briefly reviewed next on the application of non mass spectrometric Py-GC methods in the determination of polymer structure. This information is inclnded in the hope, when necessary, that chemists will be able to adapt these methods by including a mass spectrometric detailed information on polymer structure acrylates [63, 105-107], rubbers [63, 108-110], PVC [63,111-115], aliphatic polyhydrazides [116], polyoxamides [116], polyamides [117], polyether imides [118], methacrylamide [119], aromatic aliphatic polyamides [117], polyurethanes [120], chitin graft poly(2-methyl 2-oxazolone) [121, 122], polyxylyl sulfide [123-126], epoxy resins [127], polyethylene oxalate [128], polytetrafluoroethylene [129], polyvinylidene chloride [129], polyepichlorohydrin, fluorinated ethylene-propylene copolymer [129], polyvinyl fluoride [129], polyvinylidene [129], fluoride [129], SBR copolymer [129] and styrene-isoprene copolymer [130]. 

The reactivity of the pendant chloromethyl side group of polyepichlorohydrin and copolymers containing epichlorohydrin units has been used to make a variety of interesting functional polymers. In aprotic solvents such as dimethyl sulfoxide, dimethylformamide, etc., these side groups undergo substitution reactions with nucleophilic reactants such as amines (25) and... 

A variety of other blends have been examined, including mixtures of various molecular weight polyethylene glycols (228), styrene/methacrylic acid ionomer in combination with polyoxyethylene or polyoxypropylene (229), methyl methacrylate/methacrylonitrile copolymers and methyl methacrylate/glycidyl methacrylate copolymers blended with polyepichlorohydrin (230). Poly(ethyl methacrylate) and poly(ethylene oxide)... 

There are three classes of polyepichlorohydrins, the homopolymer CO and GCO, the copolymer ECO, and the terpolymer GECO, as shown in Table 7.1. The stmctuie of these is given in Figure 7.1. Each family of these elastomers has its own characteristics as illustrated in Table 7.2. 

The homopolymer CO has as good a fuel resistance as ECO, but if low-temperature properties need to be considered, either the copolymer ECO or the terpolymer GECO would be suggested. All tend to swell about 40% in Fuel C. The inclusion of 10% methanol or ethanol in Fuel C results in volume swells of 85% or 70%, respectively, for a typical ECO compound. The lower the ethylene oxide content of polyepichlorohydrin ECO compounds, the more resistant they are to fuels containing alcohols, with a CO-based one being the best. 

A few polymers cannot be cross-linked with peroxides. These polymers have a high degree of branching or many side groups. In these polymers, such as butyl rubber, polyepichlorohydrin homo- and copolymers as well as polypropylene, the addition of peroxides causes chain scission and softening rather than cross-IinMng. 

Poly (tetrafluoroethylene), PMMA, rubber hydrochloride, polyepichlorohydrin fluorinated ethylene-propylene copolymer, polyvinyl fluoride, polyvinylidene fluoride styrene butadiene copolymer Temperature programmed, pyrolysis MS - - - [45]... 

---