Unreactive poly

Sefcik and coworkers [80] were the first to use solid-state NMR to study the curing of poly(imide) oligomers terminated with reactive groups. The authors observed a clearly-resolved peak at 84 ppm in the spectrum of the unreacted poly(imide) resin, Thermid 600, due to terminal acetylene groups. On curing at 450-640 K, the decrease in intensity of this peak allowed facile... 

Polymerization of HEMA is affected by the presence of the other components of resin-modified glass-ionomers. It has been shown that HEMA itself will undergo addition polymerization more rapidly in the presence of poly(acrylic acid) than on its own [18]. However, in resin-modified glass-ionomers, pure unreacted poly(acrylic acid) may not be present for very long, and the effect of metal polyacrylate salts on the rate of polymerization of HEMA has not been studied. 

The copolymerization of methyl 4-(phenylthio)phenyl sulfoxide with poly(TFE-co-PVE) was carried out in a mixture of freon-113/ trifluoromethanesulfonic acid as the polymerization solvent for 10 hr (Scheme 1). The solvent viscosity increased at the end stage of the polymerization. The resulting polymer was washed with freon-113 and acetonitrile repeatedly to remove the unreacted poly(TFE-co-PVE) and homopolymer of polysulfonium(i9). The block copolymer was isolated with 93 % yield. It is believed that the degree of the PPS segment is estimated to be ca. 20 as an average through the completely reaction, which depends on the feed concentration ratio of the monomers( 40). 

This poly(amido-amine) was then dissolved in a suitable solvent, and treated with styrene in the presence of radical initiators, thus obtaining the final product (Scheme 4). Any unreacted poly(amido-amine) which might have been present at the end of the reaction could be extracted with methanol. 

These poly(amido-amines) can be used to prepare other types of segmented polymers. For instance, coupling with isocyanate end-capped polyurethanes leads to poly(amido-amine) - polyurethane block copolymers (40). Furthermore, polyethylene - poly(amido-amine) graft copolymers have been prepared (43) by reacting partially chlorosul-fonated polyethylene with an excess of poly(amido-amine) in the presence of triethylamine, and extracting with methanol any unreacted poly(amido-amine) at the end of the reaction (Scheme 5). 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

The PVA process is highly capital-iatensive, as separate faciUties are required for the production of poly(viayl acetate), its saponification to PVA, the recovery of unreacted monomer, and the production of acetic acid from the ester formed during alcoholysis. Capital costs are far in excess of those associated with the traditional production of other vinyl resins. 

Isobutjiene was first polymerized ia 1873. High molecular weight polymer was later synthesized at I. G. Farben by decreasiag the polymerization temperature to —75°, but the saturated, unreactive polymer could not be cross-linked iato a useful synthetic elastomer. It was not until 1937 that poly(isobutylene- (9-isoprene) [9010-85-9] or butyl mbber was iavented at the Standard Oil Development Co. (now Exxon Chemical Co.) laboratories (1). 

Phosphazene polymers are normally made in a two-step process. First, hexachlorocyclotriphosphazene [940-71 -6J, trimer (1), is polymerized in bulk to poly(dichlorophosphazene) [26085-02-9], chloropolymer (2). The chloropolymer is then dissolved and reprecipitated to remove unreacted trimer. After redissolving, nucleophilic substitution on (2) with alkyl or aryloxides provides the desired product (3). 

The stoichiometry of the redox reactions of conducting polymers (n and m in reactions 1 and 2) is quite variable. Under the most widely used conditions, polypyrroles and polythiophenes can be reversibly oxidized to a level of one hole per ca. 3 monomer units (i.e., a degree of oxidation, n, of ca. 0.3).7 However, this limit is dictated by the stability of the oxidized film under the conditions employed (Section V). With particularly dry and unreactive solvents, degrees of oxidation of 0.5 can be reversibly attained,37 and for poly-(4,4 -dimethoxybithiophene), a value of n = 1 has been reported.38 Although much fewer data are available for n-doping, it appears to involve similar stoichiometries [i.e., m in Eq. (2) is typically ca. 0.3].34,39"41 Polyanilines can in principle be reversibly p-doped to one... 

ABA type poly(hydroxyethyl methacrylate) (HEMA) and PDMS copolymers were synthesized by the coupling reactions of preformed a,co-isocyanate terminated PDMS oligomers and amine-terminated HEMA macromonomers312). Polymerization reactions were conducted in DMF solution at 0 °C. Products were purified by precipitation in diethyl ether to remove unreacted PDMS oligomers. After dissolving in DMF/toluene mixture, copolymers were reprecipitated in methanol/water mixture to remove unreacted HEMA oligomers. Microphase separated structures were observed under transmission electron microscope, using osmium tetroxide stained thin copolymer films. 

In spite of the fact that the preparation of polydichlorophosphazene nowadays can be reached in many different ways and with great efficiency (vide supra), the substitution of the chlorine atoms of this polymer to form stable poly-(organophosphazenes) is stiU a source of problems as it can be seldom driven to completeness and a very small amount of unreacted chlorines is always present in the final phosphazene material [38]. The complete ehmination of these chlorines is mandatory if the modification of the phosphazene materials over time has to be successfully prevented. 

There are over 400 different commercial alkyd resin formulations based on phthalic anhydride used in the coatings business. Alkyd resins for paints are made by reacting phthalic anhydride with a poly-alcohol (usually from naturally occurring sources rather than synthetic) that contains unreacted double bonds. The paint dries by the resin crosslinking through reaction of the double bonds under the influence of oxygen in the air. 

The progress of polyester-forming reactions between glycols and dibasic acids is easily followed by titrating the unreacted carboxyl groups in samples removed from the reaction mixture. Simple esterification reactions are known to be acid-catalyzed. In the absence of an added strong acid, a second molecule of the acid undergoing esterification functions as catalyst. The rate of the poly esterification process should therefore be written... 

Our requirements for certain applications called for the preparation of block copolymers of styrene and alkali metal methacrylates with molecular weights of about 20,000 and methacrylate contents of about 10 mol%. In this report we describe the preparation and reactions of S-b-MM and S-b-tBM. In the course of our investigation, we have found several new methods for the conversion of alkyl methacrylate blocks into methacrylic acid and/or metal methacrylate blocks. Of particular interest is the reaction with trimethylsilyl iodide. Under the same mild conditions, MM blocks are completely unreactive, while tBM blocks are cleanly converted to either methacrylic acid or metal methacrylate blocks. As a consequence of this unexpected selectivity, we also report the preparation of the new block copolymers, poly(methyl methacrylate-b-potassium methacrylate) (MM-b-MA.K) and poly(methyl methacrvlate-b-methacrylic acid) (MM-b-MA). 

Figure 3. Time dependence of the fraction R of unreacted aminostyrene residues during acetylation by 0.14 M acetic anhydride at 30°C. Methyl methacrylate copolymer in acetonitrile solution (0) linear poly-(methyl methacrylate-co-butyl methacrylate) swollen with acetonitrile Cd) methyl methacrylate copolymer crosslinked with 1 mole% ( ) and with 15 mole% ( ) ethylene dimethacrylate poly(methacrylate crosslinked with 3 mole% ethylene dimethacrylate containing entrapped poly(methyl acrylate-co-aminostyrene) ( ).

As an alternative method, poly(cyclodiborazane)s were prepared by the reaction of bis(silylimine)s with chlorodialkylboranes or with methyl dialkylborinates (scheme 18).32 This reaction proceeds via the condensation between V-silylimine and boron halide, eliminating trimethylsilyl halide followed by dimerization. However, the isolated polymer became insoluble after several hours of exposure under air, which resulted from the cross-linking reactions of unreacted trimethylsilyl groups to form trimerized hydrobenzamide derivatives. 

---