Journal of Elastomers and Plastics current issue

Studies on the Effect of Novel Antistatic Agent on the Properties of Polyurethane Foam

Wang, J., Yang, K., Zheng, X. — Wed, 04 Nov 2009 08:56:23 PST

Novel antistatic agents containing metal salt were used to prepare polyurethane foam (PUF) in this study. The effects of different conditions such as amount of antistatic agent, type and ratio of metal salt, temperature, relative humidity and time, on the surface resistivity were studied. Typically, the research of replacement of silver metal salt with tin metal salt has been conducted. Antistatic property of these composites illustrates that AgIO₃ metal salt replaced by two-thirds amount of SnCl₄ also shows excellent conductivity. Structure and other properties of these conductive PUF were examined by FTIR, DSC, and TGA. Moreover, the antistatic mechanism of these agents was put up. It was proposed that the metal salt in the antistatic agent might develop a conducting road. This can increase conductivity of the polymeric materials and decrease the corresponding surface resistivity.

Characterization of Microwave-Devulcanized Composites of Ground SBR Scraps

Wed, 04 Nov 2009 08:56:23 PST

The recycling of waste rubber has considerable significance in terms of environmental protection and energy conservation. Considering that most of the relevant literature is concerned with tire recycling, the objective of this study is to develop and characterize styrene-butadiene rubber composites containing only industrial rubber scraps devulcanized by microwave. The styrene-butadiene rubber extruded profile scraps were collected and ground under ambient conditions. The obtained powder styrene-butadiene rubber-r was physically, thermally, and chemically characterized. From the devulcanized styrene-butadiene rubber-r two composites were prepared, varying the exposure time of the powder in the microwave (3 and 4 min). These composites were compared to a control sample supplied by the industry from which the styrene-butadiene rubber extruded profile scraps were collected. Vulcanization parameters were determined by oscillatory disk rheometry. Vulcanized composites were characterized by crosslink density and physical-mechanical properties (Shore A hardness, tensile and tear strength, and compression set) before and after a postcure process. The mechanical properties of the compositions were ~25% for tensile strength and 41% for tear strength compared to the control sample. The results for the crosslink density verified those for the mechanical properties of the composites.

Effect of Metallic Salts of Glutaric Acid on the Formation of {beta}-crystalline Form in Isotactic Polypropylene

Dou, Q., Lu, Q.-L., Li, H.-D. — Wed, 04 Nov 2009 08:56:23 PST

The effects of glutaric acid and the lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, and cadmium salts of glutaric acid on the formation of β-crystalline form in isotactic polypropylene (iPP) at the crystallization temperatures 120 and 130°C have been investigated. It is found that glutaric acid and the sodium, potassium, and zinc salts of glutaric acid inhibit the formation of β-crystalline form in polypropylene. Lithium glutarate has a limited positive effect on the formation of β-crystalline form. Magnesium, calcium, strontium, barium salts of glutaric acid exhibit increased β-nucleation abilities with the increasing atomic radii of the combined metals. Cadmium glutarate is a good β-nucleating agent and the formation of β-crystalline form is favored at the crystallization temperature of 120°C. The increases in the orientation of b-axes of the nucleated iPP samples are due to the presences of sodium and zinc salts of glutaric acid.

Comparison of Interaction of Aromatic Solvents in Hybrid and Textile Biocomposites

John, M. J., Thomas, S., Varughese, K.T. — Wed, 04 Nov 2009 08:56:23 PST

Natural rubber was reinforced with sisal—oil palm hybrid fibers. Composites were prepared by varying the weight content of the fibers and chemical modification of the biofibers. The interaction of three different types of aromatic solvents, namely, benzene, toluene, and xylene with the rubber composites was analyzed. Textile composites were also prepared by sandwiching a single sheet of sisal fabric between two pre-weighed rubber sheets. The diffusion behavior of the textile composites in benzene, toluene, and xylene was also analyzed. The mechanics of diffusion was found to be different for hybrid and textile biocomposites. The swelling index factor was also calculated for all the composites. Swelling was found to be predominantly dependent on the aromatic solvent used and chemical treatments. Chemically modified composites were found to be less prone to solvent permeation.

Application of Factorial Design in Determination of Physico-Mechanical Properties of NR/SBR Alloy -- Influence of Sulfur Curing System

Manshaie, R., Hafezi, M., Nouri Khorasani, S. — Wed, 04 Nov 2009 08:56:23 PST

In this research physico-mechanical properties including tensile strength, elongation at break, hardness, resilience, abrasion resistance, and compression set of unsaturated natural rubber and styrene butadiene rubber (NR/SBR) alloy cured by sulfur curing system were investigated. Factorial design method was employed in order to formulate the sulfur curing system. Three different curing agents were used and their effects on physico-mechanical properties of the alloy were investigated. The results show that with increasing each curing agent, curing time and scorch time reduce and maximum torque increases. Tensile strength, % elongation at break, tear strength, and compression set decrease while hardness, resilience, and abrasion increase. The results show that application of factorial design significantly reduces research and development costs by decreasing the number of experimental configurations to be studied and the results are accurate. Results from factorial design procedure very well match the experimental results with accuracy in order of 2% variations.

Compatibilizing Effect of Fluororubber Grafted by {gamma}-Methacryloxypropyltrimethoxysliane in Fluororubber/Silicone Rubber Blends

Guo, J., Zeng, X., Luo, Q. — Wed, 04 Nov 2009 08:56:23 PST

The fluororubber/silicone rubber blends were prepared by using fluororubber grafted by -methacryloxypropyltrimethoxysliane as a compatibilizer. Fourier transform infrared Spectra revealed that -methacryloxypropyltrimethoxysliane has been grafted onto fluororubber backbone. The effect of the compatibilizer content on curing characteristics, stress—strain behavior, mechanical properties, heat aging properties, and oil resistance was investigated. The results showed that the mechanical properties and oil resistance of the blends were improved with increasing of the compatibilizer up to 11.8 wt%. The compatibility of fluororubber and silicone rubber phase was characterized by dynamic mechanical analysis.

Erratum

Wed, 04 Nov 2009 08:56:23 PST

M. J. John, S. Thomas and K. T. Varughese. Comparison of Interaction of Aromatic Solvents in Hybrid and Textile Biocomposites; first published on August 6, 2009, as DOI: 10.1177/0095244308099083. This version is no longer available. The version of record is published in Vol. 41, No. 6, DOI: 10.1177/0095244309099083.