Homopolymer compounds

Siding. The resin most used for siding is poly(vinyl chloride) homopolymer, compounded with modifiers, stabilizers, and pigments. Modifiers are most often acryhc esters, followed by chlorinated polyethylene or ethylene—vinyl acetate, used at 6—8 phr (parts per hundred resin). The modifier increases the impact strength of the rigid PVC. 

Chemical Name 1 -Ethenyl-2-pyrrolidinone homopolymer compound with iodine Common Name PVP-I Structural Formula ... 

Synonyms. l-Ethenyl-2-p3rrrolidinone homopolymer compound with iodine l-Vinyl-2-pyrrolidinone polymers, iodine complex Iodine-pol3winylpyrrolidone complex Pol3rvinylp3rrrolidone-iodine complex PVP-I Betadine. 

Extrusion rates are also increased by use of surface treated mica (6). The extrusion rate increased 20% for a 50 wt% filled polypropylene homopolymer compound using surface-modified mica. 

In block copolymers [8, 30], long segments of different homopolymers are covalently bonded to each otlier. A large part of syntliesized compounds are di-block copolymers, which consist only of two blocks, one of monomers A and one of monomers B. Tri- and multi-block assemblies of two types of homopolymer segments can be prepared. Systems witli tliree types of blocks are also of interest, since in ternary systems the mechanical properties and tire material functionality may be tuned separately. 

Perfluoroepoxid.es were first prepared ia the late 1950s by Du Pont Co. Subsequent work on these compounds has taken place throughout the world and is the subject of a number of reviews (1 5). The main use of these epoxides is as intermediates in the preparation of other fluorinated monomers. Although the polymerisation of the epoxides has been described (6—12), the resulting homopolymers and their derivatives are not significant commercial products. Almost all the work on perfluoroepoxides has been with three compounds tetrafluoroethylene oxide (TFEO), hexafluoropropylene oxide (HFPO), and perfluoroisobutylene oxide (PIBO). Most of this work has dealt with HFPO, the most versatile and by far the most valuable of this class of materials (4). 

EXA (exact) search retrieves the input stmcture and its stereoisomers, homopolymers, ions, radicals, and isotopicaHy labeled compounds. EAM (family) search retrieves the same stmctures as EXA, plus multicomponent compounds, copolymers, addition compounds, mixtures, and salts. SSS (substmcture) search uses a range of possible substituents and bonds in the input stmcture. CSS (closed substmcture) search is a more restrictive... 

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

Propylene oxide and other epoxides undergo homopolymerization to form polyethers. In industry the polymerization is started with multihinctional compounds to give a polyether stmcture having hydroxyl end groups. The hydroxyl end groups are utilized in a polyurethane forming reaction. This article is mainly concerned with propylene oxide (PO) and its various homopolymers that are used in the urethane industry. 

Starters. Nearly any compound having an active hydrogen can be used as starter (initiator) for the polymerization of PO. The common types are alcohols, amines, and thiols. Thus in Figure 2 ROH could be RNH2 or RSH. The fiinctionahty is derived from the starter, thus glycerol results in a triol. Some common starters are shown in Table 4. The term starter is preferred over the commonly used term initiator because the latter has a slightly different connotation in polymer chemistry. Table 5 Hsts some homopolymer and copolymer products from various starters. 

BMI comonomer (aHylphenols, propenylphenoxy compound) systems are significantly tougher than BMI homopolymers or BM-Michael-addition copolymer systems. BMI may also be toughened through elastomers and thermoplastics. 

Under certain conditions hydrogen cyanide can polymerize to black soHd compounds, eg, hydrogen cyanide homopolymer [26746-21-4] (1) and hydrogen cyanide tetramer [27027-02-2], C H N (2). There is usually an incubation period before rapid onset of polymer formation. Temperature has an inverse logarithmic effect on the incubation time. Acid stabilizers such as sulfuric and phosphoric acids prevent polymerization. The presence of water reduces the incubation period. 

The earliest study describing vulcanised polymers of esters of acryUc acid was carried out in Germany by Rohm (2) before World War I. The first commercial acryUc elastomers were produced in the United States in the 1940s (3—5). They were homopolymers and copolymers of ethyl acrylate and other alkyl acrylates, with a preference for poly(ethyl acrylate) [9003-32-17, due to its superior balance of properties. The main drawback of these products was the vulcanisation. The fully saturated chemical stmcture of the polymeric backbone in fact is inactive toward the classical accelerators and curing systems. As a consequence they requited the use of aggressive and not versatile compounds such as strong bases, eg, sodium metasiUcate pentahydrate. To overcome this limitation, monomers containing a reactive moiety were incorporated in the polymer backbone by copolymerisation with the usual alkyl acrylates. 

The homopolymer finds a variety of uses, as an adhesive component, as a base for chewing gum, in caulking compounds, as a tackifier for greases, in tank linings, as a motor oil additive to provide suitable viscosity characteristics and to improve the environmental stress-cracking resistance of polyethylene. It has been incorporated in quantities of up to 30% in high-density polyethylene to improve the impact strength of heavy duty sacks. 

Vinyl chloride-vinyl acetate copolymers have lower softening points than the homopolymers and compounds and may be processed at lower temperatures than... 

The acetal polymers are probably never supplied for use without any additives being incorporated. As mentioned in Section 19.3.1 antioxidants of the phenol alkane type are present in both homopolymers and copolymers. Acid acceptors are also believed to be widely used to absorb traces of acidic materials which attack the acetal linkage. Epoxides, nitrogen compounds and basic salts have been successfully employed. 

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. 

Part 1 (1978) Symbols for terms relating to homopolymers, copolymers and polymer compounds. 

Hepuzer et al. [91] have used the photoinduced homolytical bond scission of ACPB to produce styrene-based MAIs. These compounds were in a second thermally induced polymerization transferred into styrene-methacrylate block copolymers. However, as Scheme 24 implies, benzoin radicals are formed upon photolysis. In the subsequent polymerization they will react with monomer yielding nonazofunctionalized polymer. The relatively high amount of homopolymer has to be separated from the block copolymer formed after the second, thermally induced polymerization step. 

This section deals with investigations specifically aimed at producing homopolymers and copolymers of furan carbonyl compounds by the selective opening of the carbonyl bond. The many reports on polymerization of 2-furaldehyde which in fact deal with complicated acid-catalysed resinification reactions which involve both the formyl group and the furan ring are reviewed in Chapter VI. 

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