Thermoplastic natural rubber based on polyamide-12: Influence of blending technique and type of rubber on temperature scanning stress relaxation and other related properties

2011 ◽  
Vol 121 (2) ◽  
pp. 805-814 ◽  
Author(s):  
M. Narathichat ◽  
C. Kummerlöwe ◽  
N. Vennemann ◽  
C. Nakason
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Polyamide 12 ◽  
Thermoplastic Natural Rubber ◽  
Temperature Scanning

Novel thermoplastic natural rubber based on polyamide 12 blends

2014 ◽  
Vol 47 (8) ◽  
pp. 697-718 ◽  
Author(s):  
C Nakason ◽  
M Narathichat ◽  
C Kummerlöwe ◽  
N Vennemann
Keyword(s):  
Natural Rubber ◽  
Polyamide 12 ◽  
Thermoplastic Natural Rubber

Effect of Antioxidant on Properties of Thermoplastic Natural Rubber Based on ENR/TPU Blends

2012 ◽  
Vol 626 ◽  
pp. 229-232 ◽  
Author(s):  
Ekwipoo Kalkornsurapranee ◽  
Charoen Nakason ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann
Keyword(s):  
Thermal Properties ◽  
Natural Rubber ◽  
High Performance ◽  
Thermoplastic Polyurethane ◽  
Oxidative Degradation ◽  
The Novel ◽  
Dynamic Vulcanization ◽  
High Elasticity ◽  
Thermoplastic Natural Rubber ◽  
Temperature Scanning

Thermoplastic natural rubber based on epoxidized natural rubber (ENR) and thermoplastic polyurethane (TPU) blend was prepared via dynamic vulcanization process. The main objective is to improve thermal properties of the blends. Two types of antioxidant: phenolic antioxidant (Wingstay®L) and N-(1,3-dimethzlbutyl)-N-Phenyl-p-phenylenediamine (6PPD) were used to improve oxidative degradation of the blends. It was found that thermal properties in term of thermal elastic properties and thermal stability can be improved by adding the antioxidants and 6PPD gave the blend with the highest thermal properties. These were measured based on temperature scanning stress relaxation (TSSR) technique. Incorporation of ENR into the TPU caused reduction of the hardness, improved thermal properties, elasticity and oil resistance compared to the neat TPU. These results indicated that the novel high performance TPNRs with high elasticity can be prepared.

Investigation of Un-Vulcanized Natural Rubber by Means of Temperature Scanning Stress Relaxation Measurements

2013 ◽  
Vol 718-720 ◽  
pp. 117-123 ◽  
Author(s):  
Miao Wu ◽  
Michael Heinz ◽  
Norbert Vennemann
Keyword(s):  
Mechanical Properties ◽  
Stress Relaxation ◽  
Natural Rubber ◽  
Branch Points ◽  
Relaxation Spectra ◽  
Green Strength ◽  
Testing Method ◽  
Relaxation Measurements ◽  
Different Types ◽  
Temperature Scanning

Two different types of un-vulcanized natural rubber, air dried sheets (ADS) and SVR-3L block rubber, were investigated by a new testing method and the results are compared with other mechanical properties. It was found that green strength is strongly reduced if the sample is ther­mal­ly treated before testing. Presumably, the decrease of strength is caused by a decrease of branch points, mainly composed of phospholipids, which are linked to the a - terminal groups of the rubber molecules. The existence of two different types of branch points is indicated by relaxation spectra, obtained from temperature scanning stress relaxation (TSSR) measurements.

Determination of Crosslink Density and Network Structure of NR Vulcanizates by Means of TSSR

2013 ◽  
Vol 844 ◽  
pp. 482-485 ◽  
Author(s):  
Norbert Vennemann ◽  
Christina Schwarze ◽  
Claudia Kummerlöwe
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Network Structure ◽  
Crosslink Density ◽  
Relaxation Spectrum ◽  
Strong Impact ◽  
Relaxation Spectra ◽  
Peak Separation ◽  
Temperature Scanning

Unfilled vulcanizates based on natural rubber (NR) were investigated by temperature scanning stress relaxation (TSSR) measurements. Different sulfur based cure systems, i.e. conventional (CV), semi-efficient (SEV) and efficient (EV) vulcanization system, were used to prepare the vulcanizates. It was found that sulfur/accelerator - ratio has a strong impact on the shape of the relaxation spectrum, deduced from TSSR measurements. By deconvolution of the relaxation spectra, peak separation was performed and 3 different peaks were found in case of CV - cured samples. In contrast, only a single peak was found, in case of the EV-cured sample. After thiolamine treatment the shape of the relaxation spectra altered significantly in case of the CV-cured sample whereas the spectra of the SEV-and EV-cured sample exhibited only slight differences. Additionally, the crosslink density of the samples decreased after thiolamine treatment. This is due to selective cleavage of polysulfidic crosslinks. It has been concluded, that the significant peak in the relaxation spectrum at about 120 °C can be attributed to the cleavage of polysulfidic crosslinks. Furthermore, a linear relationship between the percentage of polysulfidic crosslinks and the sulfur/accelerator - ratio is assumed.

Thermoplastic natural rubber based on polyamide-12 blended with various types of natural rubber

2012 ◽  
Vol 45 (1) ◽  
pp. 47-75 ◽  
Author(s):  
Charoen Nakason ◽  
Maswanee Narathichat ◽  
Claudia Kummerlöwe ◽  
Norbert Vennemann
Keyword(s):  
Natural Rubber ◽  
Polyamide 12 ◽  
Thermoplastic Natural Rubber

scholarly journals Composites from Thermoplastic Natural Rubber Reinforced Rubberwood Sawdust: Effects of Sawdust Size and Content on Thermal, Physical, and Mechanical Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
High Density Polyethylene ◽  
High Performance ◽  
Physical And Mechanical Properties ◽  
Modulus Of Rupture ◽  
Shore Hardness ◽  
Thermoplastic Natural Rubber ◽  
Plastic Content

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.

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.

Aging of Natural Rubber Vulcanizates in the Presence of Dithiocarbamates

1959 ◽  
Vol 32 (3) ◽  
pp. 739-747 ◽  
Author(s):  
J. R. Dunn ◽  
J. Scanlan
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber ◽  
Protective Action ◽  
Dicumyl Peroxide ◽  
Vulcanized Rubber ◽  
Aging Properties ◽  
Photochemical Aging ◽  
Natural Rubber Vulcanizates

Abstract The thermal and photochemical aging of extracted dicumyl peroxide-, TMTD (sulfurless)- and santocure-vulcanized rubber, in presence of a number of metal and alkylammonium dithiocarbamates, has been investigated by measurements of stress relaxation. The dithiocarbamates have a considerable protective action upon the degradation of peroxide- and TMTD-vulcanizates, but they accelerate stress decay in santocure-accelerated vulcanizates. The reasons for this behavior are discussed. It is suggested that the excellent aging properties of unextracted TMTD vulcanizates are due to the presence of zinc dimethyldithiocarbamate formed during vulcanization.

Stress relaxation of natural rubber during irradiation

1969 ◽  
Vol 7 (4) ◽  
pp. 725-733 ◽  
Author(s):  
D. Evans ◽  
J. T. Morgan ◽  
R. Sheldon ◽  
G. B. Stapleton
Keyword(s):  
Stress Relaxation ◽  
Natural Rubber
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