Polystyrene macromers

Common examples of the high Tg macromers are based on polystyrene or polymethylmethacrylate (PMMA) polymers of sufficiently high molecular weight to have a high T (typically on the order of 70-100°C as measured by differential scanning calorimetry) and also to make them immiscible with the acrylic polymer backbone once the solvent or heat has been removed. Typical molecular weight of the polystyrene or PMMA macromers is on the order of 5000-10,000 Da. Their generic structure can be pictured as in Fig. 13 (shown there for polystyrene). 

MACROMER (10) is a trademark by CPC International of a new family of monomers. Because they are synthesized via anionic chemistry, their molecular weight is controlled by the ratio of monomer to initiator and they also have very narrow molecular weight distributions. The typical polymeric portions of MACROMEHf that have been investigated are polystyrene, polydiene, and blocks of the two (5, lCi). Some of the typical MACROMER functional groups that were examined are shown in Figure 8. These are shown to indicate the wide variety of functional groups that are useful for various polymerization mechanisms (4). 

The best test for functionality would be in a copolymerization study. A polystyrene with a methacrylate terminal functional group was prepared. A review of relative reactivity ratios indicated that vinyl chloride reacts very rapidly with methacrylates. Therefore, a copolymerization of the polystyrene terminated with a methacrylate functional group in vinyl chloride would be a good test case, and one should observe the disappearance of the MACROMER if the reaction is followed by using GPC analysis. 

A polystyrene with a functionality such as a methacrylate group copolymerized with a mixture of ethyl and butyl acrylate should yield a graft structure meeting the criteria of a thermoplastic elastomer as shown in Figure 13. The data in this figure show that as the MACROMER content is increased, the tensile... 

The above thermal analysis studies demonstrated the enhanced thermal stability of POSS materials, and suggested that there is potential to improve the flammability properties of polymers when compounded with these macromers. In a typical example of their application as flame retardants, a U.S. patent39 described the use of preceramic materials, namely, polycarbosilanes (PCS), polysilanes (PS), polysilsesquioxane (PSS) resins, and POSS (structures are shown in Figure 8.6) to improve the flammability properties of thermoplastic polymers such as, polypropylene and thermoplastic elastomers such as Kraton (polystyrene-polybutadiene-polystyrene, SBS) and Pebax (polyether block-polyamide copolymer). 

At the beginning, MACROMER was basically polystyrene prepared by anionic polymerization and subsequent reaction of the living end to produce a polymerizable group selected from the groups shown in Table 3 42). 

Choi et al. [53] have successfully used both water-soluble and oil-soluble initiators in the miniemulsion polymerization of styrene. Alducin and Asua [119] have studied the MWD of polystyrene miniemulsion polymerized with oil-soluble initiators. Rodriguez et al. [61] have developed a mathematical model of seeded miniemulsion polymerization with oil-soluble initiator. Blythe et al. [ 120] have successfully carried out miniemulsion polymerization of styrene with AMBN (oil-soluble). Ghazaly et al. [117] have used AIBN for the miniemulsion copolymerization of a hydrophobic bifunctional macromer. The polymerization progressed much faster when KPS was used than when AIBN was used. This may be due to the tendency of oil-soluble initiator radicals to recombine before initiating polymerization, as discussed by Luo. 

Macromer . [Sartomer] Mediacrylate-terminated polystyrene pour pt dqxes-sant used in inks, coatings, sealants, glass reinforcements, adhesives, graft ccqjolymers. 

This was attempted by Heitz et al [103] who synthesized a rigid chain copolymer of terephthalic acid and t-butylhydroquinone with attached polystyrene macromer side chains of a variety of molecular... 

Early in 1961 Waack and his coworkers synthesized polystyrene macromer... 

Recently Asami et al. improved the method of preparing (p-vinylbenzyl) polystyrene macromer by direct reaction of living polystyrene with p-vinyl-benzyl chloride, in the presence of tetrahydrofuran without using a capping agent. 

This work deals with the synthesis of epoxy ether terminated polystyrene macromers and their copol3nnerization with ethylene oxide. The purpose of this work is to obtain a unique hydrophilic-hydrophobic pol3nner, which may be used as a good emulsifying agent, electrostatic charge reducer, or compatib-lizer for pol3nner blends. 

Figure 1 shows GPC curves of the polystyrenes terminated with epichloro-hydrin and with methyl alcohol. It can be seen that molecular weight distribution of the polystyrene terminated with methyl alcohol is quite narrow = 1.05) whereas, there appears a shoulder in the GPC curve of the polystyrene terminated with epichlorohydrin, or so called epoxy ether terminated macromer, and so the polydispersity is wider 1.1-1.2). The... 

PSep% represents the actual weight percentage of polystyrene containing epoxy end group in the macromer. As shown in Table 1, it only amounts to 30-35%. This means that there existed also polystyrene not containing epoxy group. In combination with the above stated polystyrene with double molecular weight and the structure of epichlorohydrin and polystyrene anion, possible ways of the reaction between epichlorohydrin and the polystyrene anion may be postulated as follows ... 

Different kinds of solvents also exert an influence on the PSep% of the macromer formed. Table 2 shows that cyclohexane seems to be the best solvent for the synthesis of macromer. This may be attributed to the fact that cyclohexane is a comparatively worse solvent than benzene or toluene for polystyrene, which exhibits a random coil form in cyclohexane and more likely Includes the ion pair within the coil. This condition is favorable for the formation of epoxy ether terminated polystyrene. 

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