Other Copolymers

Copolymers of norbomene and cycloocta-1,5-diene can be degraded with oct-4-ene using WCl6/Me4Sn as catalyst to yield (H -I- 2K), (H -I- J -b 2K), (2H + 2K) and (2H -l-J +2K) as volatile products. Likewise copolymers of 2,3-bis(trifluoro-methyl)-norboma-2,5-diene and cyclopentene can be degraded with oct-4-ene to yield (L + 2K), (L + P-I-2K), (K-b P-t-L-b P + K), (2L-b2K) and the cyclic (L-b2P) (Stelzer 1982). 

This is in contrast to the homopolymer of L, which is impossible to degrade and the homopolymer of H, which only degrades with difficulty (Stelzer 1982 Wagener 1991a). It is clear that, in the degradation of the copolymers, it is the double bonds between H and J, and between L and P that yield to attack by metathesis. 

Other Copolymers. Reports of C n.m.r. studies of copolymers of sulphur dioxide with vinyl chloride, styrene, and various alkenes have appeared. In general. 

Co-episulphides of ethylene, propylene, and isobutylene have been analysed in terms of compositional triads and reactivity ratios. 

Many other copolymers of commercial importance have been discussed previously see Secs. 3-14c (vinyl acetate, vinylidene chloride), 3-14d (acrylic and methacrylic acids and esters, 

Nitrile rubber (NBR), a copolymer of 1,3-butadiene with 20-40% acrylonitrile, is noted for its oil resistance. More than 150 million pounds are produced annually in the United States. Applications include fuel tanks, gasoline hoses, and creamery equipment. Nitrile resin is made by copolymerizing acrylonitrile with about 20-30% styrene or methyl methacrylate in the presence of NBR or SBR rubber to yield a blend of the graft terpolymer and homocopolymer. Applications include extruded and blow-molded containers for household, automotive, and other products as well as some nonbeverage foods (spices, vitamins, candy). 

High Resolution NMR of Macromolecules, Chaps. X, XI, Academic Press, New York, 1972. Braun, D. and G. Cei, Makromol. Chem., 188, 171 (1987). 

Czerwinski, Makromol. Chem. Macromol. Symp., 10/11, 415 (1987). 

Czerwinski, Rates of Copolymerization, pp. 207-218 in Comprehensive Polymer Science, Vol. 3, G. C. Eastmond, A. Ledwith, S. Russo, and P. Sigwalt, eds., Pergamon Press, Oxford, 1989. 

Finally, we mention some other attempts that have been directed toward the preparation of copolymers poly(aniline-co-o//w-toluidine) [732, 733], poly(aniline-cothiophene) [734], poly(aniline-co-aniline with sulfonate, alkylsulfonate, carboxy-late, chloro and fluoro groups) [735], poly(aniline-co-/7-phenylene diamine) [737], poly(aniline-co-w-phenylenediamine) [736, 738], poly(aniline-co-diphenyl-amine) [164,360,739], poly(aniline-co-dithioaniline [740], as well as copolymers of diphenylamine and anthranilic acid [361] or benzidine [349], iV-vinylcarbazole and thienylpyrrole and terthiophenes [618], and aniline with aminonaphthalenesul-fonates [243]. Several other works that describe copolymers can be found among 

The copolymers discussed so far are random in that we polymerize a mixture of monomers and they are arranged in some uniform way along the polymer chain. Even in this case, long runs of one monomer or the other may occur, especially when one monomer is present in higher proportion than the other. We have already mentioned the interesting properties of styrene-butadiene block copolymers used as thermoplastic elastomers. There are many other uses for block copolymers. Template synthesis of mesoporous ceramics is currently being investigated [56]. The self-assembly characteristics of these materials is of importance. 

Even low-molecular-weight block copolymers have values for this process. If an ethylene oxide (E) polymer terminating in hydroxyls is used to start a propylene oxide (P) polymerization, a block polymer results with hydrophilic (E) and hydro-phobic (P) portions. The products at molecular weights of 1000-2000 are useful as surface-active agents. 

A third variety is the graft copolymer. In this case, branches of one monomer are grown on a main stem of a previously formed polymer molecule. For example, polyethylene can be irradiated in air with gamma rays or accelerated electrons, which leave peroxides or free radicals trapped on the polymer backbone. Exposed to a reactive monomer such as acrylonitrile (CH2=CHCN), polymerization is initiated at the free-radical sites, and branches of polyacrylonitrile grow on the polyethylene crystal stem [57]. 

All of the examples discussed so far have been free-radically polymerised systems. To conclude this section, some copolymers prepared by other routes are described briefly. 

Significant interest has been shown in the use of NMR spectroscopy to study copolymers of ethylene with, for example, propylene, butene, or hexene [5, 31-35]. This no doubt reflects the technological importance of these polymers, which are prepared using Ziegler-Natta catalysts. Whist these polymers can give rise to relatively complex carbon-13 NMR spectra, they 

Clearly, propylene is preferentially polymerised at site 1, while at site 2 ethylene and propylene copolymerise to give an approximately random copolymer. 

In a similar study by Cheng [32] on ethylene/1-butene copolymers, a two-site model was also invoked. In contrast, he found that the microstructure of ethylene/1-hexene copolymers could be described adequately using a one-site first-order Markov model [33]. Regio-irregularity in polypropylene has also been treated by Cheng using Markov statistics (see [5] and references therein). 

Havens and Reimer have used carbon-13 NMR measurements to study the sequence distribution in a series of aryl ether ketone copolymers [41]. These copolymers were based on terephthaloyl chloride (T), 1,4-diphenoxy-benzene (B), and diphenyl ether (E) and were prepared by a Friedel-Crafts reaction using either HF/BF3 or buffered AICI3 as the catalyst. The copolymers formed are comprised of T units alternating with either E or B units. 

The antiviral properties of alternating AT-vinylpyrrolidone-co-MA have received a fair amount of study. The copolymer is known as an interferon inducer.A large number of amino acids, such as histamine, atropine, and prednisolone, have been used to modify the copolymer to obtain additional antiviral, antibacterial, antiinflammatory, and hormonal active materials.The acrylic acid-co-MA polymer has also been modified to obtain antiviral materials. 

The properties of 1 1 copolymers prepared from allyl alcohol and derivatives with MA have been very briefly examined.The copolymers are soluble in a variety of organic solvents, including acetone, 2-butanone, ethanol, propanol, DMF, dimethylsulfoxide, THF, pyridine, and dilute ammonia or alkalin solutions. A similar copolymer may be prepared from monoalkyl esters of maleic acid. Copolymerization of styrene with mono-allyl maleate or fumarate hinders cyclization, due to the highly reactive styrene.  

Copolymers of styrene-, olefins-, vin d acetate-, and alkyl vinyl ether-MA were introduced commercially to fill the need for resins of low viscosity, water solubility, and high functionality. The aforesaid properties and other copolymer characteristics made for a wide range of possible uses for these materials. In this review on uses, we make no attempt to completely separate out the current uses from past and potential applications. 

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GopolymeriZation. The importance of VDC as a monomer results from its abiHty to copolymerize with other vinyl monomers. Its Rvalue equals 0.22 and its e value equals 0.36. It most easily copolymerizes with acrylates, but it also reacts, more slowly, with other monomers, eg, styrene, that form highly resonance-stabiHzed radicals. Reactivity ratios (r and r, with various monomers are Hsted in Table 2. Many other copolymers have been prepared from monomers for which the reactivity ratios are not known. The commercially important copolymers include those with vinyl chloride (VC),... 

Poly(ethyl methacrylate) (PEMA) yields truly compatible blends with poly(vinyl acetate) up to 20% PEMA concentration (133). Synergistic improvement in material properties was observed. Poly(ethylene oxide) forms compatible homogeneous blends with poly(vinyl acetate) (134). The T of the blends and the crystaUizabiUty of the PEO depend on the composition. The miscibility window of poly(vinyl acetate) and its copolymers with alkyl acrylates can be broadened through the incorporation of acryUc acid as a third component (135). A description of compatible and incompatible blends of poly(vinyl acetate) and other copolymers has been compiled (136). Blends of poly(vinyl acetate) copolymers with urethanes can provide improved heat resistance to the product providing reduced creep rates in adhesives used for vinyl laminating (137). 

Miscellaneous Copolymers. VP has been employed as a termonomer with various acryUc monomer—monomer combinations, especially to afford resins usehil as hair fixatives. Because of major differences in reactivity, VP can be copolymerized with alpha-olefins, but the products are actually PVP grafted with olefin or olefin oligomers (151,152). Likewise styrene can be polymerized in the presence of PVP and the resulting dispersion is unusually stable, suggesting that this added resistance to separation is caused by some grafting of styrene onto PVP (153). The Hterature contains innumerable references to other copolymers but at present (ca 1997), those reviewed in this article are the only ones known to have commercial significance. 

Other copolymer forms are alternating copolymers, block copolymers and graft polymers. 

Whereas Tefzel is said to be an internally stablised copolymer of TFE and ethylene, other copolymers that are compounds of similar copolymers with stabilisers of antioxidants are now also available (Hostaflon ET by Hoechst and Aflon by Asahi Glass Co.). Glass-fibre-filled grades are also available. 

Many other copolymers are mentioned in the literature and some of these have reached commercial status in the plastics or some related industry. The reason for the activity usually lies in the hope of finding a polymer which is of low cost, water white and rigid but which has a greater heat resistance and toughness than polystyrene. This hope has yet to be fulfilled. 

A number of other copolymers with vinylidene chloride as the major component have been marketed. Prominent in the patent literature are methyl methacrylate, methyl acrylate and ethyl acrylate. 

The copolymers are prepared using a mixture of dimethyl terephthalate and dimethyl naphthalate. Published data indicates a reasonably linear relationship between and copolymer composition on the lines discussed in Section 4.2, e.g. Tg for a 50 50 copolymer is about 100°C which is about mid-way between Tg figures for the two homopolymers. In line with most other copolymers there is no such linearity in the crystalline melting point (T, ). As comonomer levels are introduced drops from the values for both homopolymers and indeed crystallisation only readily occurs where one of the components is dominant, i.e. 80%. Thus commercial copolymers are usually classified into two types ... 

Table 17 Water Repellency of Cardanol-Grafted Cellulose in Comparison to Other Copolymers...

Other copolymers of acrylamide with the zwitterionic 3-(2-acrylamido-2-methylpropyldimethyl ammonio)- -propane sulfonate (AMPDAPS) monomer also have been examined. 

Thus, the results of the studies of poly(NVCl-co-NVIAz) synthesized in an aqueous medium at a temperature above the PST demonstrated that some of the copolymers exhibit typical LCST-properties, whereas other copolymers remain water-soluble upon the heating of their solutions but show the transition effects detected by HS-DSC (as well as by NMR and light scattering, see below). From these data, the following questions can be formulated ... 

PVA Particles. Dispersions were prepared in order to examine stabilization for a core polymer having a glass transition temperature below the dispersion polymerization temperature. PVA particles prepared with a block copolymer having M PS) x 10000 showed a tendency to flocculate at ambient temperature during redispersion cycles to remove excess block copolymer, particularly if the dispersion polymerization had not proceeded to 100 conversion of monomer. It is well documented that on mixing solutions of polystyrene and poly(vinyl acetate) homopolymers phase separation tends to occur (10,11), and solubility studies (12) of PS in n-heptane suggest that PS blocks with Mn(PS) 10000 will be close to dissolution when dispersion polymerizations are performed at 3 +3 K. Consequently, we may postulate that for soft polymer particles the block copolymer is rejected from the particle because of an incompatibility effect and is adsorbed at the particle surface. If the block copolymer desorbs from the particle surface, then particle agglomeration will occur unless rapid adsorption of other copolymer molecules occurs from a reservoir of excess block copolymer. 

Binary molecular co-crystals of 2,5-bis(3-pyridyl)-l,3,4-oxadiazole and 2,5-bis-(4-pyridyl)-l,3,4-oxadiazole with benzene-1,3,5-tricarboxylic and benzene-1,2,4,5-tetracarboxylic acids were studied by X-ray and thermogravimetric analysis of mass loss <2005MI1247>. Dipole moments were used to study the flexoelectric effect in guest-host mixtures of 2,5-(4-pentylbenzene)-l,3,4-oxadiazole with commercial liquid crystal hosts <2005CM6354>. The luminescence properties of many other copolymers were also investigated (see Section 5.06.12.3). 

Likewise, copolymers 90 have higher EL efficiency than homopolymers DHF-PPV 57 or MEH-PPV 13, due to more balanced charge injection and transport properties. Copolymer 90 with 7.5 wt% loading of dialkoxyphenylene comonomer gave the highest QE. The device with an ITO/PEDOT/90/Ca configuration showed remarkably higher efficiency (2.4cd/A) than devices fabricated with other copolymers in the series (0.65-1.0cd/A) [141],... 

As observed for other copolymers that exhibit an LCST (3), sodium chloride depresses the LCST of NIPAAM copolymers (Figure 6). The difference appears to be very large for NIPAAM copolymers in 0.9 M sodium chloride versus PBS (15 to over 20 C). These studies indicated that the NIPAAM-AAM copolymer that precipitated most efficiently above 55 C and below 65 C in 0.9M NaCl contained 67% NIPAAM and 33% AAM. 

Telechelic polymers, containing one or more end groups with the capacity to react with other molecules, are useful for synthesizing block and other copolymers [Fontanille, 1989 Hsieh and Quirk, 1996 Nuyken and Pask, 1989 Pantazis et al., 2003 Patil et al., 1998 Quirk et al., 1989, 1996 Rempp et al., 1988]. Living anionic polymers can be terminated with a variety of electrophilic reagents to yield telechelic polymers. For example, reaction with carbon dioxide, ethylene oxide, and allyl bromide yield polymers terminated with carboxyl, hydroxyl, and allyl groups, respectively. Functionalization with hydroxyl or carboxyl groups can also be achieved by reaction with a lactone or anhydride, respectively. Polymers with amine end... 

Block and graft copolymers differ from the other copolymers in that there are long sequences of each monomer in the copolymer chain. A block copolymer is a linear copolymer with one or more long uninterrupted sequences of each polymeric species,... 

Was used in prepn of acrylate resins and of other copolymers and polymers. Acrylate resins are thermoplastic polymers or polymers of acrylic and methacrylic acid, esters of these acids or acrylonitrile. Acrylic acid acrylonitrile and their derivatives are described in Vol 1 of Encycl, pp A96-R A97. Methacrylic acid is a-methylacrylic acid,... 

In contrast to the other copolymers in the present work, the copolymers with methyl methacrylate are expected to be random rather than perfectly alternating. Since both monomers contain an electron-poor bond, both would be classified as "acceptors."... 

Recently it was disclosed in a Japanese patent that the copolymers of hexanal with propanal, butanal and isobutanal could be used as self-developing X-ray resists of 200 — 400 mJ/cm2 sensitivity (32). Our poly(ethanal-co-butanal) showed the sensitivity of 30 mJ/cm2 on the exposure to X-ray radiation without requiring a wet development process (Table VIII). Other copolymers also functioned as a positive self developing X-ray resist. 

Other copolymers that are used instead of nitrile rubber are, for instance, chlorinated polyethylene which, in combination with PVC, gives the commercial product, Hostalit Z, of Farbwerke Hoechst. 

Health and Safety Issues. Polyesterether elastomers derived from dimethyl terephthalate, butanediol, and Ptmeg are not hazardous according to the published Materials Safety Data Sheets (MSDS) for this elastomer. Polymers of a similar structure containing isophthalic acid are also not considered hazardous. For other copolymer elastomers, the MSDS put out by suppliers should be consulted by potential users before evaluation. One environmental advantage of thermoplastic elastomers of this type is that they are melt-reprocessible and thus scrap and off-specification material and even obselete parts can be easily recycled. Up to 25% by weight of recycled material can be incorporated (see Recycling, plastics). 

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