Monomer produced, effect

Self-dissociation of the Lewis acid produces a situation more conducive to direct initiation, since the cationic moiety formed from the metal halide can attack the monomer more effectively and add onto its double bond to give the corresponding carboca-tion. 

Effect of the Polybutadiene Content. A series of ABS samples was prepared using 0.1 part TDM and varying the polybutadiene content from 5 to 50%. The introduction time of the monomers was a constant 3 hrs. When the polybutadiene content increased, the grafting efficiency increased from 2 to 40% (see Table V and Figure 3). One must note, however, that an increase in the polybutadiene content automatically decreases the monomer flow rate. It ensues that the curves in Figure 3 result from the simultaneous effects of two parameters, the polybutadiene content and the monomer flow rate. Nevertheless, it seems reasonable to think that the concomitant variations of these two parameters produce effects in the same direction. The polymer/monomer ratio increases when the polybutadiene content is increased and when the monomer flow rate is decreased. The grafting efficiency probably depends on this ratio, but the relative importance of the two parameters cannot be ascertained from our data. 

The addition of zinc chloride to allyl acetate in equivalent amounts lead to increased polymerization rates upon exposure to Co radiation. The viscosity MW of the poly(allyl acetate) produced increases with increased levels of zinc chloride [24]. The zinc chloride may assist in activating allylic-free radicals and in developing an organized array of monomers for effective polymerization. In the presence of zinc chloride it has also been proposed that the probability of... 

In contrast to expensive synthetic fibers, the use of natural fibers is a very cheap means of reinforcement, especially in countries where these natural products are readily available. Natural fibers, when compared to synthetic fibers, have a lower density and a lower tensile modulus. However, a combination of a sisal fiber with a resole type phenolic resin based on cashew nut shell liquid, a naturally occurring monomer, produces a very cost effective composite with a thermal stability greater than 200°C. The cashew nut shell liquid is a mixture of phenol, 3-(8 -pentadecenyl)phenol, 3-(8 -pentadecenyl)-5-(hydroxy)phenol, 3-(8 -pentadecenyl)-5-(hydroxy) -6-methylphenol, and2-(8-pentadecenyl-6-(hydroxy)benzoicacid [195]. 

Some results for photo-initiated grafting of monomers to brominated poly(ether-urethanes) are given in Table 4. It is clear that grafting with polar vinyl monomers produces far greater weight increases when the reactions are effected homogeneously in DMF solution. 

All monomers impart certain characteristic properties to polymers of which they form a part, but some have a particularly marked effect and can bring about significant changes in polymer behaviour even when present as only a few percent of the total monomer mix. As examples, acrylic, methacrylic acids and other unsaturated acids are used to give alkali-soluble copolymers in conjunction with methacrylic acid and acrylic esters. N-methyl acrylamide and other polyfunctional monomers produce reactive copolymers capable of secondary polymerisation or cross-linking by etherification or ionic bonding, usually after the watery portion of the emulsion has dried off. 

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