• Fibers and Polymers
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• v.3 no.4
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• pp.153-158
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• 2002

A series of waterborne polyurethanes (WBPU) were prepared from 4,4-dicyclohexylmethane diisocyanate ($H_{12}$MDI),2,2-bis(hydroxylmethyl) propionic acid (DMPA), othylenediarnine (EDA), triethylamine (TEA), and triblock glycol [TBG, ($\varepsilon$-caprolactone)$_{4.5}$-poly(tetramethylene ether) glycol (MW= 2000)-($\varepsilon$-caprolactone)$_{4.5}$: $(CL)_{4.5}$-PTMG-$(CL)_{4.5}$, MW=3000] as a soft segment. Two melting peaks of TBG at about 14$^{\circ}C$ and 38$^{\circ}C$ were observed indicating the presence of two different crystalline domains composed of CL and PTMG dominant component. The effect of soft segment content (60-75 wt%) on the colloidal properties of dispersion, and thermal and mechanical properties of WBPU films, the water vapor permeability (WVP) and water resistance (WR) of WBPU-coated Nylon fabrics, and the adhesive strength of WBPU- coated layer and Nylon fabrics was investigated. As soft segment contents increased, the water vapor permeability of WBPU- coated Nylon fabrics increased from 3615 to 4502 g/$m^2$day, however, the water resistances decreased from 1300 to 500 mm$H_2$O.O.

• Elastomers and Composites
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• v.44 no.1
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• pp.69-75
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• 2009

Asphalt sealants for the crack repair of asphalt concrete road were prepared using waste lubricant oil in this work. The waste lubricant oil was compounded with asphalt(AP-5), SBS triblock copolymer, a tackifying agent(petroleum resin), and antioxidants. Cone penetration, softening point, ductility, elongation by tensile adhesion, and resilience of asphalt sealant compounds were measured. Cone penetration of asphalt sealant compounds increased with the increase of waste lubricant oil content while their softening point, ductility, and resilience decreased. By the addition of talc as an extender, softening point and resilience of asphalt sealants increased, but cone penetration, ductility, and elongation by tensile adhesion of those decreased with the proportion of talc content. The most economic asphalt sealant which could pass an ASTM specification could be manufactured by the big decrement of petroleum resin content.

• Polymer(Korea)
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• v.28 no.2
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• pp.162-169
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• 2004

Poly[styrene-b-(ethylene-1-butene)-b-styrene] triblock copolymer (SEBS) was functionalized with 0 to 3.0 phr maleic anhydride and the amount of dicumyl peroxide used as an initiator was varied from 0 to 0.3phr. The gel content of the modified SEBS was determined by xylene extraction and poly(oxymethylene) was blended with the modified SEBS. The impact, tensile, flexural strength and morphologies of the blends were investigated. The Izod impact strength of poly(oxymethylene) was improved through its blending with modified SEBS. However, the Izod impact strength of poly(oxymethylene)/modified SEBS blend decreased above 5% modified SEBS content. Regarding the effect of dicumyl peroxide content on the Izod impact strength, the blend had a maximum Izod impact strength when poly(oxymethylene) was blended with modified SEBS prepared with 0.1 phr dicumyl peroxide. It was also confirmed by SEM micrographs that the average particle size of modified SEBS in poly(oxymethylene)/modified SEBS blends was smaller than that of SEBS in poly(oxymethylene)/SEBS blends.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.121-133
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• 2014

Block copolymers including ABA triblock architectures are useful as thermoplastic elastomers and toughened plastics depending on the relative glassy and rubbery content. These materials can be blended with other polymers and utilized as additives, toughening agents, and compatibilizers. Most of commercially available block copolymers are derived from petroleum. Renewable alternatives are attractive considering the finite supply of fossil resources on earth and the overall economic and environmental expenses involved in the recovery and use of oil. Furthermore, tomorrow's sustainable materials are demanding the design and implementation with programmed end-of-life. The present review focuses on the preparation and evaluation of new classes of renewable ABA triblock copolymers and also emphasizes on the use of carbohydrate-derived poly(lactide) or plant-based poly(olefins) having a high glass transition temperature and/or high melting temperature for the hard phase in addition to the use of bio-based amorphous hydrocarbon polymers with a low glass transition temperature for the soft components. The combination of multiple controlled polymerizations has proven to be a powerful approach. Precision-controlled synthesis of these hybrid macromolecules has led to the development of new elastomers and tough plastics offering renewability, biodegradability, and high performance.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.378-389
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• 1993

The release of steroids such as progesterone, testosterone, estrone and estradiol were investigated in two types of block copolymer matrices, which were AB type block copolymer composed of poly(γ-benzyl-L-glutamate)[PBLG] as the A segment and polyoxypropylene[POP] as the B segment and ABA type triblock copolymer composed of the A segment and poly(propylene glycol)[PPG] as the B segment. The release rates of progesterone, estradiol and testosterone through PBLG-POP1 and PBLG-POP2 matrices and those of progesterone, estrone and testosterone through GPG1 of ABA type triblock copolymer were higher in an acidic solution than in a basic one. However, the release rate of estrone through PBLG-POP1 and PBLG-POP2 matrices and that of estradiol through GPG1 of ABA type triblock copolymer were higher in a basic and neutral solutions than in an acidic one. The order of release rate in three different matrices was GPG1 > PBLG-POP1 > PBLG-POP2. The results also showed that the molecular weight of steroids is inversely proportional to the rate of release.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.241-242
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• 2007

• Proceedings of the Korean Society of Rheology Conference
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• 2000.11a
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• pp.37-40
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• 2000

• Proceedings of the Korean Society of Rheology Conference
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• 2002.11a
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• pp.5-8
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• 2002

No Abstract, See Full Text

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.147-150
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• 2008

• Proceedings of the Korean Fiber Society Conference
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• 2001.04a
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• pp.135.2-139
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• 2001