Polyisoprene, grafting

Figure 7.1.6. Result for a Py-GC/MS analysis of polyisoprene-graft-maleic anhydride with Mw = 25,000. Pyrolysis done at 60(f C in He, with the separation on a Carbowax type column.

Brass is certainly not an ideal material for this study. It would have been for better to use a polyisoprene grafted black such as prepared by LeBras and Papirer58 provided no other bonding sites were left available on the surface, and that it could be made certain that the bonded polymer could crosslink into the added rubber. 

The study of acid-base interaction is an important branch of interfacial science. These interactions are widely exploited in several practical applications such as adhesion and adsorption processes. Most of the current studies in this area are based on calorimetric studies or wetting measurements or peel test measurements. While these studies have been instrumental in the understanding of these interfacial interactions, to a certain extent the interpretation of the results of these studies has been largely empirical. The recent advances in the theory and experiments of contact mechanics could be potentially employed to better understand and measure the molecular level acid-base interactions. One of the following two experimental procedures could be utilized (1) Polymers with different levels of acidic and basic chemical constitution can be coated on to elastomeric caps, as described in Section 4.2.1, and the adhesion between these layers can be measured using the JKR technique and Eqs. 11 or 30 as appropriate. For example, poly(p-amino styrene) and poly(p-hydroxy carbonyl styrene) can be coated on to PDMS-ox, and be used as acidic and basic surfaces, respectively, to study the acid-base interactions. (2) Another approach is to graft acidic or basic macromers onto a weakly crosslinked polyisoprene or polybutadiene elastomeric networks, and use these elastomeric networks in the JKR studies as described in Section 4.2.1. 

Els and McGill [48] reported the action of maleic anhydride on polypropylene-polyisoprene blends. A graft copolymer was found in situ through the modifier, which later enhanced the overall performance of the blend. Scott and Macosko [49] studied the reactive and nonreactive compatibilization of nylon-ethylene-propylene rubber blends. The nonreactive polyamide-ethylene propylene blends showed poor interfacial adhesion between the phases. The reactive polyamide-ethylene propylene-maleic anhydride modified blends showed excellent adhesion and much smaller dispersed phase domain size. 

Very few graft copolymers based on poly(arylene ether)s have been synthesized, probably because of their chemical inertness. Klapper et al. reported grafting the polystyrene or polyisoprene onto the poly(ether ether ketone ketone) (PEEKK) by anionic deactivation.229 The carbonyl groups on tire backbone can be attacked by the polystyrene monoanion or polyisoprene anion (Mn about 3000). Due to the steric hindrance only about 30% of tire carbonyl groups can be reacted. 

In a similar manner polyisoprene-polyethylene oxide block copolymers can prepared301. It is surprising that the poly(methyl methacrylate) anion can be successfully used for the polymerization of ethylene oxide without chain transfer302. Graft copolymers are also prepared by successive addition of ethylene oxide to the poly-... 

A number of other polymers have the characteristics of TPE and some are available commercially, such as (1) 1,2-polybutadiene, (2) tran -polyisoprene (PI), (3) modified polyethylene (PE) (e.g., ethylene vinyl acetate [EVA] and ethylene ethyl acrylate [EEA]), (4) nonhydrocarbon elastomer-based TPEs, (5) metallocene elastomers/TPEs (MEs/TPEs), and (6) graft copolymeric TPEs. 

FIGURE S.4 Polystyrene (PS) branches grafted on to the multiple branch points along the polyisoprene backbone. 

Itarou H., Mays I.W., and Hadjichri-Stidis N., Regular comb polystyrene and graft polyisoprene/ polystyrene copolymers with double branches ( Centipedes ). Quality of (l,3-phenylene)bis(3-methyl-l-phenylpentylidene)dilithium initiator in the presence of polar additives. Macromolecules, 31,6697, 1998. 

A graft copolymer, comprising a polyisoprene backbone grafted with isoprene and acrylonitrile units in an unspecified arrangement that contains 85 mol % of isoprene units and 15 mol % of acrylonitrile units polyisoprene-grq/Z -poly(isoprene-co-acrylonitrile) (0.85 0.15 x)... 

Natural Rubber and Synthetic Polyisoprene Polybutadiene and Its Copolymers Polyisobutylene and Its Copolymers Ethylene-Propylene Copolymers and Terpolymers Polychloroprene Silicone Elastomers Fluorocarbon Elastomers Fluorosilicone Elastomers Electron Beam Processing of Liquid Systems Grafting and Other Polymer Modifications... 

Another approach to blending of polyacetylene with tough polymers is to form graft or block copolymers 280,281). Aldissi282) produced block copolymers by polymerizing acetylene at the ends of chains of anionic polyisoprene after conversion of... 

Allen, P. W., G. Ayrey, C. G. Moore and J. Scanlan Radiochemical studies of free-radical vinyl polymerizations. Part II. The polymerization of vinyl monomers in the presence of polyisoprenes use of C14-labeled initiators to determine the mechanism of graft-interpolymer formation. J. Polymer Sci. 36, 55 (1959). 

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