SynopsisA dual-calibration method for the determination of molecular weights and molecular weight distribution of styrene-maleic anhydride copolymers (S/MA) by gel permeation chromatography (GPC) is introduced. It might be applicable to copolymers of other type. A linear relationship of intrinsic viscosity [77] and weight-average molecular weight (a,) for unfractionated S/MA in tetrahydrofuran (THF) a t 25OC can be expressed by the equationThe maleic anhydride content of the copolymers ranges from 5 to 50 mole-%, and the a, range is from 2 X lo4 to 7 x 106. The plot of log [q] A?, versus GPC elution volume of the S/MA copolymers falls on the same curve as that of the polystyrene standards in THF.
Copolymers of 2‐hydroxyethyl acrylate, hydroxypropyl acrylate, and 2(1‐aziridinyl)‐ethyl methacrylate (M2) with styrene (M1) were prepared in benzene solution at 60°C. Benzoyl peroxide, 0.1–0.2 mole‐%, was used as initiator. Copolymer samples with the molar concentrations of M2 feed ranging from 0.10 to 0.85 were used to determine the reactivity ratios. Elemental analysis and nuclear magnetic resonance spectroscopy (NMR) were used to determine copolymer compositions. There was a solubility problem when the latter technique was applied. When samples which were completely soluble were analyzed, the results obtained from NMR and elemental analysis were in excellent agreement. The monomer reactivity ratios and the corresponding parameters for the copolymerization of (M1) with 2‐hydroxyethyl acrylate are: r1 = 0.38 ± 0.02, r2 = 0.34 ± 0.03; Q2 = 0.85, e2 = 0.64; with hydroxypropyl acrylate are: r1 = 0.45 ± 0.03, r2 = 0.36 ± 0.03; Q2 = 0.75, e2 = 0.56; with 2(1‐aziridinyl)ethyl methacrylate are: r1 = 0.53 ± 0.02, r2 = 0.63 ± 0.04; Q2 = 0.82, e2 = 0.25.
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