Poly solvent-nonsolvent tables

Most research into the study of dispersion polymerization involves common vinyl monomers such as styrene, (meth)acrylates, and their copolymers with stabilizers like polyvinylpyrrolidone (PVP) [33-40], poly(acrylic acid) (PAA) [18,41],poly(methacrylicacid) [42],or hydroxypropylcellulose (HPC) [43,44] in polar media (usually alcohols). However, dispersion polymerization is also used widely to prepare functional microspheres in different media [45, 46]. Some recent examples of these preparations include the (co-)polymerization of 2-hydroxyethyl methacrylate (HEMA) [47,48],4-vinylpyridine (4VP) [49], glycidyl methacrylate (GMA) [50-53], acrylamide (AAm) [54, 55], chloro-methylstyrene (CMS) [56, 57], vinylpyrrolidone (VPy) [58], Boc-p-amino-styrene (Boc-AMST) [59],andAT-vinylcarbazole (NVC) [60] (Table 1). Dispersion polymerization is usually carried out in organic liquids such as alcohols and cyclohexane, or mixed solvent-nonsolvents such as 2-butanol-toluene, alcohol-toluene, DMF-toluene, DMF-methanol, and ethanol-DMSO. In addition to conventional PVP, PAA, and PHC as dispersant, poly(vinyl methyl ether) (PVME) [54], partially hydrolyzed poly(vinyl alcohol) (hydrolysis=35%) [61], and poly(2-(dimethylamino)ethyl methacrylate-fo-butyl methacrylate)... 

The products obtained in IBVE-aMeSt block copolymerization were fractionated with 2-propanol, a good solvent for poly(IBVE) and a nonsolvent for poly(aMeSt). Table II shows molecular weights and compositions of typical blocking products. Figure 7 illustrates examples of 1H-NMR spectra of the 2-propanol-soluble and -insoluble fractions. 

The influence exerted by particle size on the CFV of poIy(methyl methacrylate) latices stabilized by low molecular weight (1750) poly(12-hydroxystearic acid) in n-heptane has already been presented in Section S.3.5 (see especially Table 5.6). Ethanol and n-propanol were used as nonsolvents (Napper, 1968b). As the particle size increased, the CFV was found to decrease. It was deduced therefrom that the latex particles became progressively easier to coagulate as the particle size increased because incipient instability was manifest under progressively better solvency conditions than those of 0-solvents. This assuredly implicates the van der Waals attraction between the core particles in the coagulation process since the London attraction also increases with increasing particle size. 

Similar reasoning applies to mixtures of solvents. The combination of a nonsolvent with a lower, and a nonsolvent with a higher, solubility parameter than that of the polymer often gives a good solvent for the polymer (Table 6-4). Conversely, a mixture of two solvents can be a nonsolvent. Poly(acrylonitrile) 62 = 12.8), for example, dissolves in both dimethyl-formamide (<5i = 12.1) and malodinitrile = 15.1), but not in a mixture of the two. 

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