The tensile deformation and elastic behavior of Ziegler-Natta isotactic 1-butene/ethylene (BuEt) copolymers, having a broad composition from 1.7 to 45.5 mol% of ethylene units, are studied. The heterogeneous nature of the catalytic system determines a non-uniform distribution of the comonomers along the polymer chains, and copolymers with more than 5.5 mol% of ethylene present a blocky microstructure, being composed of fractions of chains made of long and short butene sequences, which can be separated by solvent fractionating procedures. Incorporation of ethylene induces improving of drawability and decrease of rigidity with respect to homopolymer, associated with the lower crystallinity, and outstanding elastomeric behavior when ethylene amount exceeds 5.5 mol%. In these copolymers the presence of irregular fractions of chains with short butene sequences, showing crystallization of the defective and low-melting temperature form I' upon aging of the amorphous at room temperature, is responsible for the good elasticity of the materials.

研究了具有1.7至45.5 mol％乙烯单元的广泛组成的齐格勒-纳塔全同立构1-丁烯/乙烯（BuEt）共聚物的拉伸变形和弹性行为。催化系统的非均质性质决定了共聚单体沿聚合物链的不均匀分布，乙烯含量超过5.5 mol％的共聚物呈现出块状微结构，由丁烯长短链组成的链部分组成，可以通过溶剂分馏程序将其分离。当乙烯含量超过5.5mol％时，乙烯的掺入引起相对于均聚物的可拉伸性的改善和刚性的降低，这与较低的结晶度有关，并引起优异的弹性体行为。