Journal of Polymer Science Part A: Polymer Chemistry, Vol.33, No.12, 2057-2067, 1995
Synthesis and Kinetics of Polymerization of Unsaturated Monomers with Oh Groups in Their Structure .2. 3-Hydroxyneopentyl Methacrylate
The synthesis of unsaturated monomers containing one or more hydroxyl groups by reaction between polyalcohols (number of OH, n greater than or equal to 2) and monoacid chlorides has been theoretically analyzed. The difficulties were shown involved in the preparation of these monomers with a high degree of purity even in the most favorable case of the completely substituted compound. The calculated mole fractions of the two monomers that can be obtained by reaction between neopentylglycol and methacryloyl chloride were compared with the experimental ones. Kinetic experiments of the polymerization of 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate were carried out at different temperatures in 1,4-dioxane for the former monomer and dioxane and absolute ethanol for the latter. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. In homogeneous solution the values of k(p)/k(t)(1/2) for the 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate were higher than those given for methyl methacrylate. The stereostructure of the polymers derived from 3-hydroxyneopentyl methacrylate and 2-hydroxyethyl methacrylate was determined by C-13 NMR spectroscopy and the molar fractions of tactic triads and dyads were calculated from different resonance signals. The polymers are predominantly syndiotactic and follow a Bernoullian distribution of tactic sequences. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were 145 and 89 degrees C, respectively.