Glass transformation temperatures of poly(vinyl alkyl ethers) and poly(vinyl alkyl sulfides)

Abstract

SynopsisA number of poly(viny1 alkyl ethers) and poly(viny1 alkyl sulfides) of reasonably high molecular weight were prepared. Glass transformation temperatures T, of the various polymers were measured dilatometrically. In general, the T , value decreased with increasing length of the n-alkyl group. Data relating T , values of poly(viny1 n-alkyl ethers) with length of n-alkyl group were treated in terms of free volume concepts of the liquid state. Branching on the alkyl group of the polymer increased the T , value. Poly(viny1 n-alkyl sulfides) had T , values about 35°C. higher than their oxygen analogs. A comparison of poly(viny1 n-alkyl ethers) and polymers of normal a-olefins showed that the ether group and methylene group in side chains were equivalent in influencing the glass transformation temperatures. From a comparison of poly( vinyl n-alkyl ethers) and poly(n-alkyl methacrylates) it is concluded that the nature of the backbone is important in determining the ease with which side chain crystallization takes place.

Controlled cationic copolymerization of benzaldehyde with isobutyl vinyl ether using base‐assisting system

“…The T g of poly(BzA-co-IBVE) (M n ¼ 14,700, M w /M n ¼ 1.09, BzA content ¼ 26%) was 6 C, which is higher than that of poly(IBVE) (T g ¼ À20 C). 44 The single T g also supports the occurrence of successful copolymerization: namely there is no contamination of homo-poly(IBVE) and/or blocky-segmented copolymers, which would give two different T g values.…”

Synthesis and Side-Chain Crystallization of New Comb-Like Polymers from 2-Amino-4-(N-alkylanilino)-6-isopropenyl-1,3,5-triazines

“…The product was recrystallized in a similar manner as Nl4. 1 6.28 (brs, lH, CH), 7.29ppm (s, 5H, C 6 H 5 ).…”

“…Wiley et al 3 and Rogers et al 4 reported the relationships between the glass transition temperature (Tg) and the length of alkyl groups of poly(n-alkyl methacrylate). Subsequently, many studies on the Tg, the crystallization of side-chains, and the mechanical properties were reported for poly(p-nalkylstyrenes ), 5 poly(n-alkyl vinyl ethers), 6 poly(N-n-alkylmaleimides), 7 poly(n-alkyl itaconates), 8 and poly(N-n-alkylacrylamides). 9 Yokota et al1°- 13 investigated the synthsis, structure, and thermal properties of widelyspaced comb-like polymers.…”

Dynamic mechanical properties of poly(vinyl alkyl ethers)

“…The dynamic resilience has been defined as the ratio of the energy in two successive cycles of free vibration, but is commonly expressed as a percentage. The per cent dynamic resilience is equal to 100 exp { -2 ?r tan 6 1, where tan 6 is the mechanical loss factor. In the range of cure times used, the upper limit of which represents about 2.5 half-lives for the decomposition of dicumyl peroxide,8 the dynamic modulus and the dynamic resilience increase with cure time.…”