Application of thermomechanical mass spectroscopy for analysis of molecular and topological structure of rubber

2000

J. Appl. Polym. Sci.

Self Cite

Diblock amorphous topological structure of a filled vulcanizate network made of natural rubber (NR) and Emulsion Butadiene Rubber (EBR) was found. These blocks differ in the transition temperatures about 200°C. Dual transitions of such rubbers have been assigned as a motion of the mixed soft block [low glass transition temperature (T g )] in the glassy state and the motion in elements of a network around physical and chemical crosslinking sites in a rigid block (high T g ), respectively. Compaction of the topological structure of a high-temperature block during curing (manifested by the growth of T g ) was noticed. The molecular weight distribution of the chains between the junctions of the network and shares of these amorphous blocks in the structure of the rubber network vs curing time were calculated using the methodology shown. Introduction of Perkalink 900 at constant quantity of sulfur changes a structure of the junctions in the tested rubber network from mixed (10 -15% of chemical bonds, and remaining are cluster type and topological junctions) into practically all chemical bonds. Optimal curing time evaluated by the thermomechanical analysis, at which molecular structures formed in both blocks reflect the equilibrium state of adsorption layers of two rubbers introduced into the compound, is close to that evaluated by the vulcametric tests. The location of the molecular weight distribution curve in both blocks one against another depends on rubber formulation. Also, a fact that crosslinks are gathered, as was predicted by Vilgis and Heinrich calculations, was confirmed experimentally.

Section: Resultssupporting

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Section: Resultsmentioning

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Section: Introductionmentioning

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See 3 more Smart Citations

Structure of natural rubber/emulsion butadiene rubber (NR/EBR) vulcanizates

Jurkowska

Ol’khov

2000

J. Appl. Polym. Sci.

Self Cite

Structure of natural rubber/emulsion butadiene rubber (NR/EBR) vulcanizates

Jurkowska

Ol’khov

2000

J. Appl. Polym. Sci.

Self Cite

Diblock amorphous topological structure of a filled vulcanizate network made of natural rubber (NR) and Emulsion Butadiene Rubber (EBR) was found. These blocks differ in the transition temperatures about 200°C. Dual transitions of such rubbers have been assigned as a motion of the mixed soft block [low glass transition temperature (Tg )] in the glassy state and the motion in elements of a network around physical and chemical crosslinking sites in a rigid block (high Tg ), respectively. Compaction of the topological structure of a high‐temperature block during curing (manifested by the growth of Tg ) was noticed. The molecular weight distribution of the chains between the junctions of the network and shares of these amorphous blocks in the structure of the rubber network vs curing time were calculated using the methodology shown. Introduction of Perkalink 900 at constant quantity of sulfur changes a structure of the junctions in the tested rubber network from mixed (10–15% of chemical bonds, and remaining are cluster type and topological junctions) into practically all chemical bonds. Optimal curing time evaluated by the thermomechanical analysis, at which molecular structures formed in both blocks reflect the equilibrium state of adsorption layers of two rubbers introduced into the compound, is close to that evaluated by the vulcametric tests. The location of the molecular weight distribution curve in both blocks one against another depends on rubber formulation. Also, a fact that crosslinks are gathered, as was predicted by Vilgis and Heinrich calculations, was confirmed experimentally. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 732–742, 2000

On the correlation between characteristics of topological and molecular structures and mechanical properties of NR/chlorinated polyethylene rubbers

Jurkowska¹,

J of Applied Polymer Sci

2003

Chlorinated polyethylene (CPE) taken as a modifier for NR rubber compound changes the mechanical properties of their vulcanizates. With the help of a novel thermomechanical methodology it was found that it also influences the structures of both the tested master batches and the vulcanizates. Some characteristics of the structure of NR/CPE rubbers obtained by using thermomechanical analysis (TMA) correlate satisfactorily with their mechanical properties measured at static and dynamic conditions. This supports our previous conclusion about the suitability of TMA to study some of the underlying reasons for changes in rubber properties resulting from rubber formulation, compounding, and processing.