Thermal ageing and γ-radiation resistance of polyisoprene /chlorosulphonated polyethylene rubber blends

The effect of carbon black (average particle size 26nm) and wood flour (particle size from 300 to 400 μm) on thermal ageing and γ-radiation resistance of polyisoprene /chlorosulphonated polyethylene rubber blend (NR/CSM) was studied. The tensile strength of the aged samples was determined, after conditioning at 70°C during 72h. The radiation exposure of samples was performed at two doses: 212 and 400 kGy.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Properties of elastomeric materials based on polychloroprene/chlorosulfonated polyethylene rubber blends

In this work the elastomeres based on polychloroprene/chlorosulphonated polyethylene rubber blends (CR/CSM) intended for rubber-metal bonding has been studied. The rheographs and curing characteristics of blends reinforced by active precipitated silica and diatomaceous earth were obtained using a Monsanto rheometer. Crosslinking has been performed by sulphur at 160 °C up to optimum cure time. Temperature dependence of storage modulus (E’), tanδ and glass transition temperature were determinated by mechanical spectroscopy. Adhesion strength has been measured by two methods. It was concluded that a adhesion strength value can be increased by using nano fillers as reinforcing agensPhysical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Curing characteristics of chlorosulphonated polyethylene and natural rubber blends

The dependence of the Mooney scorch time and cure index on the blend ratio of chlorosulphonated polyethylene/natural rubber (CSM/SMR 20 CV) and chlorosulphonated polyethylene/chlorinated natural rubber (CSM/Pergut S 40) blends were determined in the temperature range from 120 C to 160 C using a Monsanto Mooney viscometer. Semi-efficient vulcanization systems were used for the study. The morphology of the fracture surface of the crosslinked systems was determined by Scanning Electron Microscopy (SEM). The results showed that the scorch time decreased with increasing SMR 20 CV and Pergut S 40 contents. This observation is attributed to the increasing solubility of sulfur, as the content of SMR 20 CV and Pergut S 40 in the composition increased. For temperatures greater than 140 C, the dependence of the scorch time on blend ratios diminishes, as enough thermal energy is available to overcome the activation energy of vulcanization. The differing curing characteristics of the two blends is explained by the compatibility factor of the respective blend. Morphological analysis of the blends shows a very satisfactory agreement

Thermostability and surface morphology of nano- and micro-filled NBR/CSM and CR/CSM rubber blends

Acrylonitrile-butadiene rubber (NBR), polychloroprene rubber (CR). chlorosulphonated polyethylene rubber (CSM) and their blends were cross-linked with sulphur, ethylene-thiourea. magnesium oxide or their combination. The effect of nano- and micro- particle sized of 35 pphr SiO2 on the thermostability and surface morphology of all the crosslinked systems,vas investigated. Identification of the structure of nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems was carried out by Fourier transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) extension. The thermal stability of the nano- and micro- particle sized SiO2 filled NBR/CSM and CR/CSM crosslinked systems were carried out by thermogravimetric analysis (TGA). The glass transition temperature (T-g) of the samples was determined by differential Scanning calorimetry (DSC). The morphology of the fracture surface of the crosslinked systems was carried out by scanning electron microscope (SEM). The results show when filled with nano-particle sized of SiO2 NBR/CSM and CR/CSM polymer matrix have a strong peak from SiO-C at 1079 cm(-1). This suggests the an interaction between the SiO2, which should lead to an increased thermal stability, higher values of T-g, better dispersion the nano-SiO2 and more polish, without cracks than micro-filled NBR/CSM and CR/CSM crosslinked systems

The High-Energy Irradiation Ageing of Reinforced Elastomers Based on Rubber Blends

Elastomers are very often used in severe environments, for instance, in nuclear power plants, where they may be degraded by high-energy radiation and heat. The ageing behaviour of materials used in different equipments is very important. Elastomers based on chlorosulfonated polyethylene (CSM) are used for cable jacketing materials and have excellent radiation resistance needed in nuclear power stations. In the current work, the influence of gamma-irradiation dose (100, 200 and 400 kGy) on the ageing of reinforced blends based on CSM, styrene butadiene rubber (SBR) and natural rubber (NR) has been evaluated. The content of silica in CSM/SBR and CSM/NR rubber blends was varied. The curing behavior of compounds was estimated using the oscillating disk reometer. The irradiation of nano composites has been performed in air in the Co 60 radiation sterilization unit with the dose rate of 10 kGy h(-1). The thermal properties were studied by thermogravimetric test. The mechanical properties (hardness, modulus at 100% elongation, tensile strength and elongation at break) were determined before and after irradiation. A decrease in the elastic modulus and in the strain at break has been observed with increasing irradiation. At higher doses, the network chain scissions become the main degradation process, the cross-linked topology becomes irregular, and material contains more and more weak zones, which deteriorate the ultimate properties.4th International Conference on Radiation and Applications in Various Fields of Research (RAD), Proceedings, May 23-27, 2016, Nis, Serbi

The effect of gamma irradiation on ethylene propylene diene terpolymer/chlorosulphonated polyethylene rubber blend cured with different systems

This work aimed to study the effects of gamma irradiation on the properties of ethylene propylene diene terpolymer/chlorosulphonated polyethylene rubber blend (EPDM/CSM) 50/50 reinforced with 50 phr (parts per hundred rubber) of carbon black and crosslinked either with sulphur/tetramethyl thiuram disulphide or dicumyl peroxide. Irradiation dose rate were 100, 200 and 400 kGy h-1. It was observed that doses higher than 200 kGy practically destroy the assessed properties for all obtained elastomeric materials, irrespective of used curing system. However samples cured with sulphur showed a pronounced decrease in mechanical properties.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

The Effect of Gamma Radiation on the Ageing of Sulfur Cured Nr/Csm and Nbr/Csm Rubber Blends Reinforced By Carbon Black

In this work the effect of the gamma-radiation dose on ageing of carbon black reinforced elastomeric materials was studied. The compounds based on natural rubber/chlorosulfonated rubber blend (NR/CSM) and butadiene acrylonitrile rubber/chlorosulfonated rubber blend (NBR/CSM) (50 50 w/w) with different loadings (0, 20, 40, 50, 60, 80 and 100 phr) of the filler with the average particle size of 40 nm were cured by sulfur. The obtained elastomeric composites were subjected to radiation doses (100, 200, 300 and 400 kGy) in the presence of oxygen. The changes of material mechanical properties were estimated after radiation accelerated ageing. By using Fourier transform infrared measurements (ATR-FTIR) it was assessed that after exposure to doses of 100 kGy alcohols, ethers, lactones, anhydrides, esters and carboxylic acids are formed in materials. The formation of shorter polyene sequences and aromatic rings in aged samples are assumed on the basis of the obtained spectra

Curing and Mechanical Properties of Chlorosulphonated Polyethylene Rubber Blends

In this paper, the curing and mechanical properties of two series of prepared blends, i.e., chlorosulphonated polyethylene (CSM)/isobutylene-co-isoprene (IIR) rubber blends and chlorosulphonated polyethylene (CSM)/chlorinated isobutylene-co-isoprene (CIIR) rubber blends were carried out. Blends were prepared using a two-roll mill at a temperature of 40-50 degrees C. The curing was assessed using a Monsanto oscillating disc rheometer R-100. The process of vulcanization accelerated sulfur of pure rubbers and their blends was carried out in an electrically heated laboratory hydraulic press under a pressure of about 4 MPa and 160 degrees C. The stress-strain experiments were performed using a tensile tester machine (Zwick 1425). Results indicate that the scorch time, t(s2), and optimum cure time, t(c90), increase with increasing CSM content in both blends. The value of modulus at 100 and 300% elongation and tensile strength increases with increasing CSM content, whereas elongation at break shows a decreasing trend The enhancement in mechanical properties was supported by data of crosslink density in these samples obtained from swelling measurement and scanning electron microscopy studies of the rubber blends fractured surfaces

Gamma-radiation aging of silica filled chlorosulphonated polyethylene/ butadiene acrylonitrile rubber blends

In this applicative work curing behavior, mechanical properties and gammaradiation aging of silica filled elastomeric nanocomposites based on rubber blend: butadiene acrylonitrile rubber (NBR) and chlorosulphonated polyethylene rubber (CSM) were used as network precursors. The vulcanization characteristics were assessed for NBR/CSM rubber blends (50:50, w/w) using oscillating disc rheometer. The gamma radiation resistance of composites was determined from the tensile properties (hardness, tensile strength and elongation at break) after prolonged exposure to γ-irradiation (dose rate of 10 kGyh-1 and total absorbed dose of 100, 200 and 400 kGy

Influence of different functionalization methods of multi-walled carbon nanotubes on the properties of poly(L-lactide) based nanocomposites

This paper presents influence of the type of carbon nanotube functionalization on properties of poly(L-lactide) (PLLA) based nanocomposite materials. For this purpose surface modifications of multi-walled carbon nanotubes (MWCNTs) were performed by chemical and irradiation techniques, while thermo gravimetric analysis, UV-Visible and Fourier-transform infrared (FT-IR) spectroscopies confirmed successful covalent functionalization. Series of PLLA bionanocom-posites with different contents of functionalized MWCNTs (0.7; 1.6; 2.1 wt%), were synthesized via ring-opening solution polymerisation of L-lactide. FT-IR analysis confirmed that grafting of L-lactide, under controlled condition, is possible to perform starting from the surface of functionalized MWCNTs. From differential scanning calorimetry results it was concluded that even low contents of chemically and irradiation functionalized MWCNTs had a significant effect on thermal properties of the prepared nanocomposites, raising the values of melting and glass transition temperatures. Thermogravimetric analysis (TGA) has shown that the degradation onset temperature for composites with chemically functionalized MWCNTs, was much higher than that for the neat poly(L-lactide) sample and composites with irradiation functionalized MWCNTs. Morphology studies by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that poly(L-lactide) covered surfaces and separated functionalized MWCNTs. Good dispersion of carbon nanotubes in polymer matrix enabled conductivity of synthesized materials, as determined by conductivity tests