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A study has been made of the dynamic mechanical relaxation behavior of a 97% cis polypentenamer and its hydrogenated derivatives. The starting polypentenamer is wholly amorphous and derivatives were synthe­sized having melting points from -11 to 131 °C and degrees of crystallinity from 2 to 80%. Three relaxations are dis­cernible in the temperature range from -160 °C to the melting point and these are labeled a, {3, and 1' in order of de­creasing temperature. The a relaxation occurs only in the crystalline derivatives. In the derivatives of low crystallini­ty, it originates from motions accompanying melting; in derivatives of high crystallinity, …

Two series of cyano-substituted polypentenamers and ·their hydrogenated derivatives have been studied by dynamic mechanical and dielectric relaxation in the temperature range from -160 to 110°C and at frequencies from 3.5 Hz to 10 kHz. Series I contains 7.4 mol % cyano groups and series II contains 20 mol % cyano groups. The amorphous cyanopolypentenamers display one major mechanical and dielectric relaxation region asso­ciated with motions accompanying the glass transition and labeled /3. A small secondary relaxation, labeled 'Y, is also discernible in the mechanical E" results. The semicrystalline hydrogenated derivatives exhibit three relaxation regions labeled a, /3, and 'Y …

Melting points (Tm's) and glass transition temperatures (Tg's) of stereoregular poly(methyl a-chlo­roacrylates), poly(ethyl a-chloroacrylates), and poly(isopropyl a-chloroacrylates) have been determined by differ­ential scanning calorimetry (DSC). Relaxation processes accompanying these Tg's and secondary relaxation phe­nomena have been studied by dynamic mechanical and dielectric relaxation. It was found that the extrapolated Tg values for high molecular weight syndiotactic poly(alkyl a-chloroacrylates) and high molecular weight isotactic po­ly(alkyl a-chloroacrylates) differed by the following amounts: 92° for the methyl esters; 83° for the ethyl esters; and 68° for the isopropyl esters. A secondary relaxation, labeled fl, and associated with motions of the ester side chains, …

The dielectric relaxation behavior of ethylene-carboxylic acid copolymers has been studied over the frequency ° range of °SO Hz to 10 f Hz and over the temperature range of -160 C to+ 100 C. The copolymers studied consisted of four acrylic acid and two methacry­lic acid copolymers of varying acid content. In the temperature and frequency region investigated, two dielectric dispersions occur and these are labelled B' and yin order of decreasing temperature. The B' dispersion may be quantitatively accounted for on the basis of the orientation of free carboxylic acid groups. The concentra­tion of these groups is assessed from …

A study has been made of the relaxation phenomena in three series of glassy polyurethans in the temperature range from -190 to 100° and at various frequencies up to 110 Hz using dynamic mechanical and dielectric relaxation. The structures of the repeat units of the three series are given in eq 1-3. Several overlapping relaxation peaks are discernible in the temperature and frequency region investigated. All of these relaxations arise largely from motion in the amorphous phase. The following assignments of the various relaxation peaks to specific molecular motions have been made on the basis of comparisons both within and …