Rheo-Optical Studies of High Polymers. XXI. The Deformation Process and Crystal Transformation in Polybutene-1

Abstract

ABSTRACT:The crystal transformation from modification 2 to modification 1 in unstrained polybutene-I films was observed by the infrared absorption and refractive index methods. The crystal transformation and orientation during stress-strain measurements were also observed by means of the infrared dichroism method developed by us. The crystal transformation in a fresh sample begins at about 30 min after the sample preparation, and the degree of transformation increases with increasing time until it reaches about 0.9. at 50 hr and 1.0 about 3 weeks after the sample preparation. The rate of crystal transformation could be expressed by an equation of the same form as that for the one-dimensional crystallization rate.Stress-strain curves, degree of crystal transformation vs. strain curves as well as infrared dichroic ratio vs. strain curves for film specimens having different initial degrees of crystal transformation differ remarkably. On the basis of these experimental results, the deformation and crystal transformation processes during stree-strain measurements under constant rate of elongation are discussed.

The effect of a synthetic double layer hydroxide on the rate of II→I phase transformation of poly(1-butene)

“…Figure 2b shows for example the rate of disappearance of phase II as a function of time, extracted from the data in Figure 2a. For the quantification of the kinetics of the II!I phase transition, the disappearance of phase II, rather than the increase in phase I, was followed because it is known that, together with the phase transition, a post-crystallization phenomenon takes place, during which part of the amorphous polymer crystallizes in phase I [17,18,25,27]. The calculations were also done considering the amount of phase II as a ratio of the sum of the peaks of phases I and II [25], obtaining analogous results because the initial amount of phase I was almost always negligible.…”

Stretching behavior of the butene‐1/ethylene random copolymer: A direct correspondence between triggering of II‐I phase transition and mechanical yielding

“…Actually, the fact that stretching can accelerate II‐I transition has been recognized for decades . The qualitative relation of stretching‐induced phase transition has been well accepted for long time that the severer the stretching is, the higher the degree of phase transition is.…”

“…Actually, the fact that stretching can accelerate II-I transition has been recognized for decades. [18,[54][55][56][57][58][59] The qualitative relation of stretching-induced phase transition has been well accepted for long time that the severer the stretching is, the higher the degree of phase transition is. However, the experimental results revealing the quantitative correlation between the degree of phase transition and mechanical response are rarely reported.…”

Stretching‐induced phase transition of the butene‐1/ethylene random copolymer: Orientation and kinetics

“…It has been reported for decades that deformation can promote the transition of PB‐1 Form II into Form I . Goldbach performed the tensile experiments of PB‐1 Form II crystallite at a constant stress.…”

“…14,16,[18][19][20][21][22][23] This transformation process takes weeks under quiescent condition, 9,14,24 which limits the practical application. However, stretching can significantly accelerate the transition process, [25][26][27][28] which is attracting increasing attention from both academia and industry.…”