• Journal of Adhesion and Interface
• /
• v.3 no.2
• /
• pp.30-39
• /
• 2002

The effect of cure accelerator content on the change in crosslink density by thermal aging was studied for silica-filled natural rubber (NR) vulcanizates. Influence of silane coupling agent was also investigated. N-tert-Butyl-2-benzothiazole sulfenamide (TBBS) and bis-(3-(triethoxysilyl)-propyl)-tetrasulfide (TESPT) were used as a cure accelerator and a silane coupling agent, respectively. The crosslink density increased by thermal aging and the increasing level became larger as the aging temperature increased. The degree of crosslink density change of the vulcanizates without the silane coupling agent was larger than that of the vulcanizates containing the silane coupling agent. For the vulcanizates silane coupling agent, the activation energy for the crosslink density change decreased with increase of the cure accelerator content in the vulvanizate.

• Elastomers and Composites
• /
• v.45 no.3
• /
• pp.223-229
• /
• 2010

We investigated the effects of processing geometry of silica-filled isobutylene-isoprene rubber (IIR) compounds on its mechanical properties and silica dispersion, using a two roll mill and an internal mixer (banbury mixer). The compound processed with the two roll mill showed the longer induction time ($t_2$), higher maximum torque ($T_{max}$), and better silica dispersion than the compound processed with the internal mixer; however, showed slightly the lower cure index ($t_{90}$). The mechanical properties (hardness, 300% modulus, tensile strength, elongation) of the compound processed with two roll mill were higher than compound done with the internal mixer.

• Elastomers and Composites
• /
• v.49 no.3
• /
• pp.245-252
• /
• 2014

FT-IR measurement and the physical properties of polyurethane adhesive prepared from the polyol, isocyanate, 2-HEMA and other acrylate monomers were examined. The softening point, viscosity, adhesion strength and mechanical properties of the PU adhesives were reviewed by Ring and Ball method, Brookfield viscometer and universal test machine, respectively. Results revealed that increment of both PPG amount and butyl acrylate content decreased softening point, adhesion strength, tensile strength and 100% modulus. However as 2-HEMA and MDI content increased the mechanical properties including tensile strength, 100% modulus increased, and also the viscosity and NCO content increased.

• Elastomers and Composites
• /
• v.23 no.3
• /
• pp.213-222
• /
• 1988

The thermal decomposition of poly(n-butyl methacrylate)(Pn-BMA) was studied using a dynamic and isothermal thermogravimetry in nitrogen gas with 50ml/min at several heating rates from 1 to $20^{\circ}C/min$, and at several heating temperature from 320 to $370^{\circ}C$. The mathematical techniques used for calculation of activation energy were Kissinger, Anderson, Chatterjee-Conrad, Friedman, Fuoss, Ozawa and isolthermal method. The range of activation energies obtained using the several techniques was between 43 and 51Kcal/mol except Chatterjee-Conrad and this range agreed with each other very well. The thermal degradation of Pn-BMA was considered to be carried out by main chain scission.

• Elastomers and Composites
• /
• v.47 no.1
• /
• pp.75-81
• /
• 2012

Acrylic rubber was synthesized using ethyl acrylate. butyl acrylate, methoxyethyl acrylate as main monomers and glycidyl methacrylate as cure site monomer by emulsion polymerization. Rubber compound was made by adding 2,2-bis[4-(4-aminophenoxy)phenyl]propane as crosslinking agent. Increase of ethyl acrylate content in the main monomer ratio resulted in enhancement of heat resistance due to decrease of glass transition temperature in acrylic rubber. And also oil resistance was increased with increasing content of ethyl acrylate because ethyl acrylate has the highest ester concentration in the three main monomers. With content of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, both tensile strength and elongation were increased until 2 phr, but in higher content than that, they decreased owing to reduction of viscosity and elongation by increase of crosslinking density.

• Elastomers and Composites
• /
• v.52 no.1
• /
• pp.35-47
• /
• 2017

A comprehensive survey of the available literature showed that in the last few decades, there has been a growing interest in the use of thermoplastic vulcanizates (TPVs). TPVs are the second largest group of soft thermoplastic elastomers (TPEs) after styrene-based block copolymers, and offer a wide range of potential and proven applications, including in mechanical rubber goods, under-the-hood applications in the automotive field, industrial hose applications, electrical applications, consumer goods, and soft touch applications. Over the last two decades, TPVs have shown a strong and steady market growth (~12% per year). Commercialized TPVs are commonly based on blends of ethylene propylene diene monomer (EPDM) rubber and polypropylene (PP), and to a lesser extent on combinations of butyl or nitrile rubber with PP. EPDM/PP TPVs are characterized by finely dispersed crosslinked EPDM rubber particles (particles size varying between 0.5 and $2.0{\mu}m$) distributed in a continuous thermoplastic PP matrix. If the rubber particles of such a blend are small enough and if they are vulcanized well enough, then the properties of the blend are generally improved. This review article introduces various topics and aspects relevant to EPDM/PP TPVs. The development of TPVs, the use of various types of crosslinking systems and co-agents as crosslinking agents for PP/EPDM blends, the morphology and rheology of TPVs, and their typical end-use applications are also reviewed.

• Polymer(Korea)
• /
• v.31 no.1
• /
• pp.8-13
• /
• 2007

To overcome drawbacks of the nylon 6/poly (acrylonitrile-co-butadiene-co-styrene) (ABS) blend, nylon 6 blend with poly (acrylonitrile - co-styrene - co-acrylic rubber) (ASA) which containing poly (butyl acrylate) as a rubber phase in substitute of poly (butadiene) in ABS, was examined. Poly (styrene-co-maleic anhydride) (SMA) containing 25 wt% of maleic anhydride (MA) or poly (styrene- co-acrylo-nitrile-co-maleic anhydride) (SANMA) containing less than 3 wt% MA was used as a compatibilizer to fabricate blends having high impact strength. Changes in the mechanical properties of nylon 6/ASA blend with compatibilizer content were similar with those of nylon 6/ABS blend. Blends haying high impact strength was produced when blends contained more than about 20 wt% rubber. Blends containing SAM or SANMA as a compatibilizer were stayed in a injection molding machine at the molding temperature and afterwards specimens for the examination of the impact strength was prepared. Impact strength of blends containing SMA was decreased with retention time, while that of blends containing SANMA was not changed with retention time.

• Elastomers and Composites
• /
• v.29 no.1
• /
• pp.9-17
• /
• 1994

Methylmetharylate grafted latex(MGL) was prepared by emulsion graft copolymerization of methyl methacrylate onto natural rubber latex(NRL) by using t-butyl hydroperoxide and tetraethylene pentamine in an aqueous medium. Blending of MGL and NRL with different mixing ratio carried out and viscosity and particle size distribution of blend latex were determined. It was found that the optimum condition of mature time, vulcanizing temperature and time for preparation of blend latex films were investigated. latex films prepared by dipping process were meaured. As the reuslt, blend latex(NR-d-MG) films obtained from two-dipping system were more excellent than NR and MG film obtained from one-dipping system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.540-541
• /
• 2012

• Elastomers and Composites
• /
• v.43 no.3
• /
• pp.157-165
• /
• 2008

Suspension polymerization was carried out to synthesize poly(butyl methacrylate) (PBMA) composite particles containing carbon black. Water was selected as a reaction medium, hydrophobic silica as a stabilizer and azobisisobutyronitrile as an initiator. Concentration of stabilizer was varied from 0.67 to 2.55 weight% with respect to the water, and that of initiator was varied from 0.25 to 3.00 weight% with respect to the butyl methacrylate (BMA) monomer. All polymerization reactions were conducted at 75$^{\circ}C$. It is found that stabilizer concentration has no impact on reaction kinetics, while an increase in initiator concentration enhances polymerization reaction rate. Increase of carbon black concentration from 1 to 3 to 5 wt% into PBMA displayed progressive decrease in reaction conversion. The particle diameter of PBMA composite particles containing carbon black was found to be between 5 and 30 ${\mu}m$. Glass transition was determined to range from 23.8 to 24.7$^{\circ}C$, irrespective of variation in the concentration of stabilizer, initiator or carbon black.