The Effect of Sequence Structure of Polyisoprene on its Crystallization and Reinforcement

Induced Crystallization ◽

C Nmr

soprene can be polymerized into three types of isomeric units, cis-1, 4, trans-1, 4 and 3, 4-units. Dyad or triad sequences of these units were investigated by 13C-NMR, which the signals are assigned for the sequences as well as the special linkages, head-to-head and head-to-tail structures. The crystallization ability of polyisoprene was mainly dependent on these sequence structures and was studied in this paper, including cold crystallization and stress-induced crystallization. As a result, the samples with regular sequence structure had better crystallized ability which will be as the guidance for the polymerization.

Effects of the interfacial stress-induced crystallization on the matrix crystalline morphology and the mechanical properties of glass fiber-reinforced high density polyethylene composites

Journal of Adhesion Science and Technology ◽

10.1163/156856100742267 ◽

2000 ◽

Vol 14 (11) ◽

pp. 1405-1421 ◽

Cited By ~ 10

Author(s):

Yuncan Zhang ◽

Ruizhu Chen ◽

Zhongzhi Hui

Keyword(s):

Mechanical Properties ◽

Glass Fiber ◽

High Density Polyethylene ◽

High Density ◽

Interfacial Stress ◽

Crystalline Morphology ◽

Glass Fiber Reinforced ◽

The Matrix ◽

Influence of stress-induced crystallization on the dimensional stability of monoaxially drawn poly(ethylene terephthalate)

Polymer ◽

10.1016/0032-3861(93)90854-4 ◽

1993 ◽

Vol 34 (7) ◽

pp. 1418-1422 ◽

Cited By ~ 13

Author(s):

L. Mascia ◽

Z. Fekkai

Keyword(s):

Dimensional Stability ◽

Ethylene Terephthalate ◽

Poly Ethylene Terephthalate ◽

Poly Ethylene ◽

Stress induced crystallization in thermoplastic elastomers

Colloid & Polymer Science ◽

10.1007/bf01418191 ◽

1986 ◽

Vol 264 (4) ◽

pp. 323-331 ◽

Cited By ~ 3

Author(s):

R. Stadler ◽

W. Gronski

Keyword(s):

Thermoplastic Elastomers ◽

Stress-Induced Crystallization Of Elastomers

Low-Temperature Behaviour of Elastomers ◽

10.1163/ej.9789004157200.i-188.21 ◽

2011 ◽

pp. 97-114

Keyword(s):

Elastomer Structures and ‘Cold Crystallization’

Rubber Chemistry and Technology ◽

10.5254/1.3535204 ◽

1979 ◽

Vol 52 (1) ◽

pp. 207-212 ◽

Cited By ~ 1

Author(s):

M. Bruzzone ◽

E. Sorta

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Melting Point ◽

Natural Rubber ◽

Crystallization Rate ◽

Cold Crystallization ◽

Structural Defects ◽

Strain Induced Crystallization ◽

Abstract In a great number of applications an ideal elastomer should satisfy, to a certain extent, both of the following requirements: (1) nearly instantaneous crystallization upon application of strain (strain induced crystallization) and (2) slow or no crystallization when cooled at the temperature of maximum crystallization rate (cold induced crystallization). A noteworthy case of (2) is elastomer crystallization in a strained state. The connection between the points (1) and (2) has not been clearly understood up to now, but it is known that some crystallizable elastomers fulfil the requirements of both (1) and (2) better than others. From an experimental point of view, cold induced crystallization kinetics are substantially easier to measure than those of very fast strain induced crystallization. The phenomenon of cold induced crystallization in natural rubber, NR, has been known since the very beginning of elastomer technology and the tendency of natural rubber to crystallize by cooling has been overcome by crosslinking it with sulphur (vulcanization) without impairing its ability to crystallize by stretching (Goodyear, 1836). The synthesis of cis-polyisoprenes (IR) and cis-polybutadiene (BR) of different microstructural purity (different cis content) gave the possibility of changing the crystallization rate. It has also been reported that the very fast cold crystallization of trans-polypentenamer (TPA) could be reduced by lowering the trans content. The same fact had been observed earlier for trans-polychloroprene. There is a general agreement in postulating that the reduction of the crystallization rate, obtained either by cross-linking or by chain regularity reduction, can be linked with the lowering of the melting point. In both cases the low level of structural defects introduced in the chains does not affect the glass transition temperature in such a way as to vary the crystallization rate. The aim of this paper is to emphasize the importance of the variations of the glass transition temperature and melting point on the elastomeric cold crystallization rate and the way these may be used in planning new elastomer structures.