Dynamic mechanical and dielectric properties of substituted polypentenamers with phosphonate side groups and their hydrogenated derivatives have been studied. Methyl esters, acids, and salts were investigated at two concentrations, 6.5 and 11.1 mole percent. In the unhydrogenated derivatives, one principal relaxation, labeled (3, is observed mechanically in the temperature range from-160 to 100°C. This (3 relaxation arises from micro-Brownian segmental motion accompanying the glass transition. Its temperature is substantially affected by the substituent concentration while its breadth is affected by the chemical nature of the substituent. An extended "rubbery plateau" region exists in the acid and salt derivatives. The dielectric results generally reinforce the mechanical assignments. In the hydrogenated derivatives, three relaxations labeled a, (3, and 'Y in order of decreasing temperature occur mechanically in this temperature range. The temperatures at which the a and (3 relaxations occur depend greatly on the chemical nature of the substituents, the substituent concentration, and the thermal history of the sample; while the 'Y relaxation appears to be independent of these variables. Suggested assignments for the relaxations observed in these polymers, based on the duiil glass transition theory of Boyer for semicrystalline polymers, have been proposed. The dielectric results are consistent with the proposed assignments.
Polypentenamer has been sulfonated using a 1: 1 complex of sulfur trioxide and triethyl phosphate in chloroform. A range of polymers containing from 1.9 to 19.1 mol % sulfonate groups was prepared by this reagent and isolated in the form of sodium salts. These materials are initially free from covalent cross-links but cross-linking occurs with aging unless the polymers are stabilized with a free-radical scavenger such as hydroquinone. The unsaturated bonds in these materials can be removed by hydrogenation with ptoluenesulfonyl hydrazide. The hydrogenated derivatives are crystalline and no longer require a stabilizer to inhibit cross-linking. Both the unsaturated and hydrogenated polymers are hydrophilic.
Three types of pressure dependent deformation processes have been observed for the short glass fiber reinforced composites of poly(vinyl chloride) (PVC). A unique deformation behavior, observed for the first time, features a sharp drop in stress followed by shear yielding in the matrix. Competitive pressure dependent failure processes in the composites are strongly affected by “debonding” at the fiber‐matrix interface. A new general pressure dependent yield criterion for PVC and its composites was elucidated.
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