Cure characteristics and mechanical properties of natural rubber/reclaimed rubber blends were studied. The minimum torque values of the blends were lower than that of the gum compound. The (maximum-minimum torque) and scorch time decreased with increasing reclaim content. The cure rate of the blends were lower than that of the virgin compounds. The tear strength was improved by the addition of reclaimed rubber. Tensile strength, elongation at break, and resilience decreased with increasing reclaim loading. The heat buildup was higher for the blends.

Mechanical properties and thermal degradation of natural rubber compounds containing castor oil were studied to evaluate its suitability as plasticizer. Naphthenic oil was used as a reference plasticizer. The cure time was marginally lower in the case of castor oil mixes, probably due to the presence of free fatty acids in it. The tear strength and modulus were better in the case of mixes containing castor oil, while most of the other mechanical properties were comparable to the mixes containing naphthenic oil. The heat build up and compression set were higher than that of the naphthenic oil mixes. Thermal studies showed an increase of 8 °C in the temperature of initiation of degradation and an increase of 6 °C in the temperature at which the peak rate of degradation occurred. The peak rate of degradation was comparable to that of the reference compound

Cure characteristics and mechanical properties of acrylonitrile butadiene rubber/reclaimed rubber blends were studied. Minimum torque, (maximum -minimum) torque, scorch time, cure time and cure rate decreased in presence of reclaimed rubber. Tensile strength, elongation at break and compression set increased with increase in reclaim content. Resilience and abrasion resistance decreased with reclaim loading. Heat build up was higher for the blends. The ageing resistance of the blends was inferior to that of the gum compound.

SYNOPSISMechanical and dynamic mechanical behavior of short Kevlar fiber-filled thermoplastic polyurethane (TPU) have been studied with respect to fiber loading and orientation. The strength of the composite is improved at higher fiber content with a minimum at 10 phr of fibers. Storage and loss moduli (E', E") are increased and tan 6 , -is reduced progressively with fiber loading, the effect on moduli being more pronounced at post-T, temperatures. Anisotropy in strength is evident beyond 15 phr fiber loading. Impact strength is reduced considerably at all fiber loadings irrespective of fiber orientation. Study of the fracture surface by scanning electron microscopy (SEM) shows good correlation between the modes of failure and strength of the composites. SEM study of the extracted fibers shows the existence of a kinking stage through which the fiber undergoes severe breakage during processing.

Cure characteristics and mechanical properties of styrene butadiene rubber reclaimed rubber blends were studied. The blends showed improved processability, as indicated by the minimum torque values. Cure characteristics like minimum torque, (maximum-minimum) torque, cure time and cure rate decreased in the presence of reclaimed rubber. Tensile strength, tear strength, elongation at break were higher for blends. Resilience decreased with reclaim content. Compression set and abrasion loss were higher in the blends.