Elastocaloric effect in vulcanized natural rubber and natural/wastes rubber blends

The rheometer curing curves of neat natural rubber (NR) and neat chloroprene rubber (CR) with maleide F (MF) exhibit considerable crosslinking torque at 180 °C. This indicates that MF can crosslink both these rubbers via Alder-ene reactions. Based on this knowledge, MF has been introduced as a co-crosslinking agent for a 50/50 blend of NR and CR in conjunction with accelerated sulfur. The delta (Δ) torque obtained from the curing curves of a blend with the addition of 1 phr MF was around 62% higher than those without MF. As the content of MF increased to 3 phr, the Δ torque was further raised to 236%. Moreover, the mechanical properties, particularly the tensile strength of the blend with the addition of 1 phr MF in conjunction with the accelerated sulfur, was around 201% higher than the blend without MF. The overall tensile properties of the blends cured with MF were almost retained even after ageing the samples at 70 °C for 72 h. This significant improvement in the curing torque and the tensile properties of the blends indicates that MF can co-crosslink between NR and CR via the Diels–Alder reaction.

Download Full-text

Thermoplastic elastomer based on high-density polyethylene/natural rubber blends: rheological, thermal, and morphological properties

Polymers for Advanced Technologies ◽

10.1002/pat.972 ◽

2008 ◽

Vol 19 (2) ◽

pp. 85-98 ◽

Cited By ~ 14

Author(s):

C. Nakason ◽

S. Jamjinno ◽

A. Kaesaman ◽

S. Kiatkamjornwong

Keyword(s):

Natural Rubber ◽

High Density Polyethylene ◽

Thermoplastic Elastomer ◽

High Density ◽

Morphological Properties ◽

Rubber Blends

Download Full-text

Reinforcing efficiency and compatibilizing effect of sol–gel derived in situ silica for natural rubber/chloroprene rubber blends

RSC Advances ◽

10.1039/c4ra09415h ◽

2014 ◽

Vol 4 (102) ◽

pp. 58816-58825 ◽

Cited By ~ 21

Author(s):

Bharat P. Kapgate ◽

Chayan Das

Keyword(s):

Natural Rubber ◽

Sol Gel ◽

Rubber Blends ◽

In Situ Silica ◽

Chloroprene Rubber ◽

Compatibilizing Effect

The strong CR/in situ silica interaction causes filler accumulation at the interphase and enhances the compatibility and reinforcement in the NR/CR blend.

Download Full-text

Effects of accelerator type on stress relaxation behavior and network structure of aged natural rubber/chloroprene rubber vulcanizates

Journal of Elastomers & Plastics ◽

10.1177/0095244316663268 ◽

2016 ◽

Vol 49 (5) ◽

pp. 381-396 ◽

Cited By ~ 7

Author(s):

Farzad A Nobari Azar ◽

Murat Şen

Keyword(s):

Stress Relaxation ◽

Natural Rubber ◽

Network Structure ◽

Structural Changes ◽

Relaxation Behavior ◽

Stress Relaxation Behavior ◽

Rubber Blends ◽

Chloroprene Rubber ◽

Weather Changes ◽

Behavior Network

Natural rubber/chloroprene rubber (NR/CR) blends are among the commonly used rubber blends in industry and continuously are exposed to severe weather changes. To investigate the effects of accelerator type on the network structure and stress relaxation of unaged and aged NR/CE vulcanizates, tetramethyl thiuram disulfide, 2-mercaptobenzothiazole, and diphenyl guanidine accelerators have been chosen to represent fast, moderate, and slow accelerator groups, respectively. Three batches have been prepared with exactly the same components and mixing conditions differing only in accelerator type. Temperatures scanning stress relaxation and pulse nuclear magnetic resonance techniques have been used to reveal the structural changes of differently accelerated rubber blends before and after weathering. Nonoxidative thermal decomposition analyses have been carried out using a thermogravimetric analyzer. Results indicate that there is a strong interdependence between accelerator type and stress relaxation behavior, network structure, cross-linking density, and aging behavior of the blends. Accelerator type also affects decomposition energy of the blends.

Download Full-text