• Elastomers and Composites
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• v.49 no.3
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• pp.210-219
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• 2014

In this study, the acrylic pressure sensitive adhesive (PSA) for the optical functionality sheet was prepared by blending liquid isoprene rubber. The acrylic PSA was synthesized with butyl acrylate, acrylic acid, 2-ethylhexyl acrylate and 2-hydroxyethyl methacrylate. Toluene was used to a solvent for polymerization. Liquid isoprene rubber (LIR-50) was blended with the acrylic PSA and blend ratio was 0 ~ 50 wt%. According to the results, the adhesive transfer, which was the big problem of acrylic adhesive, was reduced with the addition of LIR-50. The secondary bonding of LIR-50 with substrate did not occurred due to absence of polar group in LIR-50. The peel strength and adhesive transfer were decreased by UV curing and the degreed of decrease depended on the amounts of photoinitiator and UV irradiation time. On the other hand holding power increased drastically by increasing amounts of photoinitiator and UV irradiation time.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.851-856
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• 1994

Compatibility and viscoelasticity in non-solvent type pressure sensitive adhesive of styrene-isoprene-styreno(SIS) block copolymer with tackifier resin were investigated. In the isoprene phase of SIS block copolymer, it was found that it's compatibility with $C^5$ petroleum resin was good, but that with Coumarone-indents resin was not so good. The magnitudes of peel strength, tack, and holding power were as follows : $C^5$ petroleum resin>rosin ester resin>coumarone-indene resin. The tackifier resin with good compatibility in rubber phase was also effective. However, with plateau modulus value of $1{\times}10^6-3{\times}10^6dyn/cm^2$, the effect of pressure sensitive adhesives was excellent.

• Journal of the Society of Disaster Information
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• v.12 no.3
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• pp.242-248
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• 2016

This paper presents features of impermeable asphalt pavement material that uses thermoplastic GMA-based polymer(SIS, Stylene Isoprene Stylene) to improve the waterproof performance. Furthermore, as part of this study, the aerodynamic characteristics of the asphalt paving materials, using the newly suggested thermoplastic polymer, are identified through experiments. In the experiment, the aerodynamic characteristics were analyzed by testing on stability, flow values, porosity, dynamic stability, tensile strength ratio and skid resistance in accordance with KS standard and ASTM standard.

• Elastomers and Composites
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• v.56 no.4
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• pp.223-233
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• 2021

In this study, epoxidized liquid isoprene rubber (E-LqIR) was used as a processing aid in a silica-filled natural rubber compound to improve the fuel efficiency, abrasion resistance, and oil migration problems of truck and bus radial tire tread. The wear resistance, fuel efficiency, and extraction resistance of the compound were evaluated according to the molecular weight of E-LqIR. Results of the evaluation showed that the E-LqIR compound had a lower chemical crosslink density than that of a treated distillate aromatic extract (TDAE) oil compound because of the sulfur consumption of E-LqIR. However, the filler-rubber interaction improved because of the reaction of E-LqIR with silica and crosslink with the base rubber by sulfur. As the molecular weight of E-LqIR increased, crosslink with sulfur was facilitated, and the filler-rubber interaction improved, resulting in improved abrasion resistance. The fuel efficiency performance of the E-LqIR compound was poorer than that of the TDAE oil compound because of the low chemical crosslink density and hysteresis loss at the free chain end of E-LqIR. However, the fuel efficiency performance improved as the molecular weight of E-LqIR increased.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.71-71
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• 1992

• Elastomers and Composites
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• v.10 no.1
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• pp.28-32
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• 1975

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.217-226
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• 2015

To investigate the distributions of BVOCs (Biogenic Volatile Organic Compounds) from mountain near mega city and their role in forest atmospheric, BVOCs and their oxidized species were measured at a 41 m tower in Mt. Taehwa during May, June and August 2013. A proton transfer reaction-mass spectrometer (PTR-MS) was used to quantify isoprene and monoterpenes. In conjunction with BVOCs, $O_3$, meteorological parameters, PAR (Photosynthetically Active Radiation) and LAI (Leaf Area Index) were measured. The average concentrations of isoprene and monoterpenes were 0.71 ppbv and 0.17 ppbv, respectively. BVOCs showed higher concentrations in the early summer (June) compared to the late summer (August). Isoprene started increasing at 2 PM and reached the maximum concentration around 5 PM. In contrast, monoterpenes concentrations began to increase 4 PM and stayed high at night. The $O_3$ maximum was generally found at 3 PM and remained high until 5 PM or later, which was concurrent with the enhancement of $O_3$. The concentrations of BVOCs were higher below canopy (18 m) than above canopy, which indicated these species were produced by trees. At night, monoterpenes concentrations were negatively correlated with these of $O_3$ below canopy. Using MEGAN (Model of Emissions of Gases and Aerosols from Nature), the emissions of isoprene and monoterpenes were estimated at 1.1 ton/year and 0.9 ton/year, respectively at Mt. Taehwa.

• Korea-Australia Rheology Journal
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• v.19 no.4
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• pp.227-232
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• 2007

The use of various shearing apparatuses to study the phase behavior of poly(styrene-b-isoprene) diblock copolymer micelles is described. A DMTA rheometer was modified so that one can apply oscillatory shear and obtain the scattering pattern along the shear gradient direction. A cone and plate shear cell was designed to access scattering along the shear vorticity direction, and both oscillatory and steady shear can be applied. The most popular way to employ steady shear on relatively low viscosity fluids is to use a Couette cell, because a high shear rate can be readily achieved without disturbing the sample by overflow. In this work, oscillatory shear was used to obtain a single crystal-like scattering pattern, and thereby to examine the mechanism of the thermotropic transition between face-centered cubic (fcc) and body-centered cubic (bcc) lattices. By applying the steady shear, the response of the fcc lattices to various shear rates is discussed.

• Macromolecular Research
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• v.16 no.1
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• pp.51-56
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• 2008

Spherical micelles of poly(styrene-b-isoprene) (SI) diblock copolymers in selective solvents have been reported to pack onto either face-centered cubic (fcc) or body-centered cubic (bcc) lattices. The selection rule for fcc and bcc lattices has been understood in terms of the intermicellar potentials, and they have been quantified using the ratio of the corona layer thickness to the core radius, $L/R_c$, as suggested by McConnell and Gast. In order to test the validity of the McConnell-Gast criterion, this study compared the $L/R_c$ values from various solutions i.e. nine SI copolymers in several different selective solvents. The McConnell-Gast criterion was not found to be a determining factor, even though it could explain the fcc/bcc selection qualitatively. From the phase diagrams, the transition between fcc and bcc phases was also considered as a function of concentration and temperature, and their physical mechanisms are discussed based on the recent mean-field calculation reported by Grason.

• Elastomers and Composites
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• v.53 no.2
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• pp.80-85
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• 2018

Chloro isobutylene isoprene rubber (CIIR) and ethylene propylene diene monomer (EPDM) compounded with other formulation chemicals, depending on the polymer blend, were prepared by mechanical mixing. After manufacturing the rubber vulcanizate by compression molding with a hot press, the mechanical and thermal properties including thermal conductivity, rebound resilience of the CIIR/EPDM blends were measured. As the EPDM rubber content increased, hardness and tension set showed a tendency to increase. Pure CIIR exhibited the lowest tensile strength; however, tensile strength increased with loading of EPDM rubber. On the other hand, in CIIR rubber, which is usually a low-rebound elastomer owing to a high damping effect, rebound resilience exhibited an increasing trend as the content of EPDM rubber increased. As the EPDM rubber content increased, thermal stability was improved due to reduction of decomposition rate in the rubber region of the blend vulcanizate.