scholarly journals Crosslink density and rheometric behaviour of natural rubber/chloroprene rubber blends

2019 ◽  
Vol 505 ◽  
pp. 012113
Author(s):  
I Surya ◽  
M Z Siswarni
Keyword(s):  
Natural Rubber ◽  
Crosslink Density ◽  
Rubber Blends ◽  
Chloroprene Rubber

scholarly journals Rheometer Evidences for the Co-Curing Effect of a Bismaleimide in Conjunction with the Accelerated Sulfur on Natural Rubber/Chloroprene Rubber Blends

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1510
Author(s):  
Marek Pöschl ◽  
Shibulal Gopi Sathi ◽  
Radek Stoček ◽  
Ondřej Kratina
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Crosslinking Agent ◽  
Alder Reaction ◽  
Diels Alder ◽  
Ene Reactions ◽  
Rubber Blends ◽  
Diels Alder Reaction ◽  
Chloroprene Rubber

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.

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

RSC Advances ◽  
2014 ◽  
Vol 4 (102) ◽  
pp. 58816-58825 ◽  
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.

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

2016 ◽  
Vol 49 (5) ◽  
pp. 381-396 ◽  
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.

scholarly journals The effects of alkanolamide addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR) / chloroprene rubber (CR) blends

2018 ◽  
Vol 34 ◽  
pp. 01030 ◽  
Author(s):  
Indra Surya ◽  
Syahrul Fauzi Siregar ◽  
Hanafi Ismail
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Tensile Properties ◽  
Crosslink Density ◽  
Tensile Modulus ◽  
Palm Stearin ◽  
Swelling Behaviour ◽  
Elongation At Break ◽  
Cure Characteristics ◽  
Chloroprene Rubber

Effects of alkanolamide (ALK) addition on cure characteristics, swelling behaviour and tensile properties of silica-filled natural rubber (NR)/chloroprene rubber (CR) blends were investigated. The ALK was synthesized from Refined Bleached Deodorized Palm Stearin (RBDPS) and diethanolamine, and incorporated into the silica-filled NR/CR blends as a non-toxic rubber additive. The ALK loadings were 0.0, 1.0, 3.0, 5.0 and 7.0 phr. It was found that the ALK exhibited shorter scorch and cure times and higher elongation at break of the silica-filled NR/CR blends. The ALK also exhibited higher torque differences, tensile modulus and tensile strength at a 1.0 phr of ALK loading and then decreased with further increases in the ALK loading. The swelling measurement proved that the 1.0 phr loading of ALK caused the highest degree in crosslink density of the silica-filled NR/CR blends.

Application of NR Gloves Reclaim: Cure and Mechanical Properties of NR/Reclaim Rubber Blends

2013 ◽  
Vol 844 ◽  
pp. 437-440 ◽  
Author(s):  
Sitisaiyidah Saiwari ◽  
Eman Lohyi ◽  
Charoen Nakason
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Chemical Process ◽  
Crosslink Density ◽  
Maximum Torque ◽  
Rubber Blends ◽  
Functional Sites ◽  
Cure Behavior ◽  
Blend Ratios

Reclamation of waste natural rubber gloves is carried out by mechano-chemical process using MBTS as reclaiming agent. The reclaim rubber is later blended with a virgin natural rubber at various blend ratios. The cure behavior and mechanical properties of the re-vulcanized blends are evaluated in comparison to the properties profile of the virgin materials. A significant increase in re-vulcanization rate is observed with increasing reclaim rubber contents. This property is most likely a consequence of the presence of active functional sites in the reclaim rubber. Additionally, the maximum torque as well as a torque difference increase with increasing reclaims rubber contents which are attributed to an increase in crosslink density of the blends. Moreover, the crosslink density also plays a major role in mechanical properties of the NR/reclaim rubber blends.

Influence of Silanized-Silica and Carbon Black on the Cure and Mechanical Properties of Natural Rubber/Recycled Chloroprene Rubber (NR/rCR) Blends

2016 ◽  
Vol 1133 ◽  
pp. 191-195
Author(s):  
Siti Zuliana Salleh ◽  
Hanafi Ismail ◽  
Zulkifli Ahmad
Keyword(s):  
Tensile Strength ◽  
Carbon Black ◽  
Natural Rubber ◽  
Morphological Characterization ◽  
Filler Loading ◽  
Rubber Blends ◽  
Roll Mill ◽  
Cure Time ◽  
Chloroprene Rubber ◽  
Silanized Silica

The loadings effect of carbon black and silanized-silica filled 75/25 phr/phr of natural rubber/recycled chloroprene rubber (NR/rCR) blends were compared with the unfilled NR/rCR blends. Different filler loading between in the range of 10- 40 phr was used. The rubber blends were prepared by using a laboratory two-roll mill and rheometric characteristics were studied using the Monsanto moving die rheometer (MDR 2000) at 150 °C. The addition of CB and silanized-silica showed different trend in scorch and cure time but showed similar trend in torques. The incorporation of both fillers caused higher tensile strength than that unfilled rubber blends. By comparison, the silanized-silica filled NR/rCR blends showed higher tensile strength than CB filled NR/rCR blends. Morphological characterization as observed from SEM justified these results.

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