Homopolymer solution, lattice density

Droscher et al prepared copolymers of trioxane and dioxolane which were almost completely crystalline for low comonomer concentrations. Even if a segregation was observed with an enrichment of the amorphous phase in comonomer units, an insertion of the -(CH2-CH2-O)- (E) segments in the crystalline -(0-CH2)n- domain was demonstrated. With respect to the trioxane homopolymer lattice, a lateral expansion (cell parameter a) and a contraction along the chain axis (cell parameter c) roughly proportional to the amount of comonomer were observed up to a mole fraction of 0.1. The density and melting point of the lattice decreased accordingly. It was also shown that for the same comonomer amount, the lattice cell of these extended-chain copolymer crystals was larger than the one observed as-crystallized from the melt or solution. 

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