Statistical Theory of Linear Polymers. II. Elasticity of Vulcanized Rubber

1947 ◽  
Vol 2 (3) ◽  
pp. 51-56 ◽  
Author(s):  
Ryogo Kubo
Keyword(s):  
Statistical Theory ◽  
Linear Polymers ◽  
Vulcanized Rubber

scholarly journals Reinforcement of Styrene Butadiene Rubber Employing Poly(isobornyl methacrylate) (PIBOMA) as High Tg Thermoplastic Polymer

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1626
Author(s):  
Abdullah Gunaydin ◽  
Clément Mugemana ◽  
Patrick Grysan ◽  
Carlos Eloy Federico ◽  
Reiner Dieden ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molar Mass ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Linear Polymers ◽  
Elongation At Break ◽  
Vulcanized Rubber ◽  
Rubber Compounds ◽  
Styrene Butadiene

A set of poly(isobornyl methacrylate)s (PIBOMA) having molar mass in the range of 26,000–283,000 g mol−1 was prepared either via RAFT process or using free radical polymerization. These linear polymers demonstrated high glass transition temperatures (Tg up to 201 °C) and thermal stability (Tonset up to 230 °C). They were further applied as reinforcing agents in the preparation of the vulcanized rubber compositions based on poly(styrene butadiene rubber) (SBR). The influence of the PIBOMA content and molar mass on the cure characteristics, rheological and mechanical properties of rubber compounds were studied in detail. Moving die rheometry revealed that all rubber compounds filled with PIBOMA demonstrated higher torque increase values ΔS in comparison with rubber compositions without filler, independent of PIBOMA content or molar mass, thus confirming its reinforcing effect. Reinforcement via PIBOMA addition was also observed for vulcanized rubbers in the viscoelastic region and the rubbery plateau, i.e. from −20 to 180 °C, by dynamic mechanical thermal analysis. Notably, while at temperatures above ~125 °C, ultra-high-molecular-weight polyethylene (UHMWPE) rapidly loses its ability to provide reinforcement due to softening/melting, all PIBOMA resins maintained their ability to reinforce rubber matrix up to 180 °C. For rubber compositions containing 20 phr of PIBOMA, both tensile strength and elongation at break decreased with increasing PIBOMA molecular weight. In summary, PIBOMA, with its outstanding high Tg among known poly(methacrylates), may be used in the preparation of advanced high-stiffness rubber compositions, where it provides reinforcement above 120 °C and gives properties appropriate for a range of applications.

Elastic and Thermoelastic Properties of Rubberlike Materials. A Statistical Theory

1941 ◽  
Vol 14 (3) ◽  
pp. 596-605 ◽  
Author(s):  
Eugene Guth ◽  
Hubert M. James
Keyword(s):  
Statistical Theory ◽  
Second Law Of Thermodynamics ◽  
Statistical Interpretation ◽  
Free Rotation ◽  
Extended Form ◽  
Thermoelastic Properties ◽  
Vulcanized Rubber ◽  
Carbon Carbon Bond ◽  
Kinetic Effects ◽  
Molecular Compounds

Abstract A statistical theory of the elasticity of rubber and similar high-molecular compounds was proposed by one of the authors several years ago, and an extended form of the theory was presented recently. The theory is applied here to vulcanizates, and shows the dependence of stress on both temperature and deformation for both extension and compression. The foundations of the theory will be stated precisely, inasmuch as some recent articles dealing with it are likely to lead to misunderstandings concerning the assumption of free rotation and structure of long-chain compounds, such as vulcanized rubber. The possible ro^le of kinetic effects for the rubber type of elasticity has been discussed qualitatively by Wöhlisch, Busse, Karrer, Meyer, Susich and Valkó, and Shacklock. The first quantitative theory was developed by one of the authors in 1934 and published later, partly in collaboration with Mark. In the statistical theory, the main assumption is that of quasi-free rotation in a rubber molecule around a single carbon-carbon bond. An important consequence of this free rotation is that the molecules are coiled in the unstretched state. The contraction of stretched rubber is due mainly to the tendency of the stretched chain to change from a less probable stretched form back to the most probable coiled form. This happens in accordance with the statistical interpretation of the second law of thermodynamics, and is not caused by forces. Our theory, then, is that the kinetic motion of freely rotating groups in the rubber molecule is the main cause of contraction.

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