선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- As mentioned above, micro-porous structure generally shows higher water vapor permeability. In this study, in order to make direct coated febric to have micro-porous structure, WBPU/PVA were used as coating materials for fabrics, and then water soluble polymer PVA were removed by dissolution ofPVA in water. Waterborne polyurethane-urea (WBPU) was synthesized by prepolymer mixing process using isophorone diisocyanate (IPDI)/2, 2-bis(hydroxymethyl)propionic acid (DMPA)Zpoly (tetramethylene ether) glycol (PTMG)/ethylenediamine (EDA)/triethylamine (TEA) in an emulsion system.
- Coating materials were prepared by blending WBPU dispersion with aqueous PVA solution. The effect of PVA content on the viscosity of coating materials, and the effects of PVA content and dissolution conditions on the dissolution% of PVA and number/mean size of micro-pores of coating material films were examined. The changes of water vapor permeability of coated Nylon fabrics according to the changes of PVA content and dissolution condition were studied.
대상 데이터
- ) were dried at 100 ℃ under vacuum (1 ~2 mmHg) for 5 hrs before being used. Dibutyl tin diaurate (DBTDL, Aldrich Chemical Co.), thickener (L75N, Bayer, Germany) and hardener (ARF-30, main component: polyisocyanate, solid content: > 99, NCO%: 20, Dongsung, Busan, Korea) were used without further purification. Poly(vinyl alcohol) (PVA, 99+ hydrolyzed, Mw =89, 000~98, 000, Aldrich Chemical Co.
- WBPU/water soluble polymer PVA (5, 15, and 30 wt%) blends as coating materials were prepared by blending WBPU dispersion with PVA solution. The coating materials were coated to Nylon fabrics. It was found that the maximum/optimum contents of PVA for stable emulsions were about 30 wt%.
- Coating to Nylon Fabrics. The coating materials were formulated from WBPU/PVA/thickener (L75N, Bayer)/ hardener or WBPU/PVA/hardener. The WBPU/PVA blend containing high PVA content (30 wt%) showed a high viscosity (> 3, 000 cps).
이론/모형
- The reaction mixture was allowed to react at 85 ℃ until the theoretical NCO content was reached. The change of NCO content during reaction was determined by the standard dibuthylamine back-titration method (ASTM D1638). Then, methyl ethyl ketone (MEK: about 20 wt%) was added to the NCO-terminated prepolymer mixture to adjust the viscosity of reaction mixture.
- The samples were coated in conventional manner with a thin layer of gold palladium to prevent changing. The water vapor permeability was determined using an evaporation method described in ASTM E9663-T. The mouth of the test dish is covered with test specimen, and the edges are sealed with sealing material.
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