Chapter 1 . IntrodutionPolymer: high molecular weight= number average molecular weight (수평균 분자량)= weight average molecular weight (중량평균 분자량)= viscosity average molecular weight (점도평균 분자량)polymer 라고 할 때 통상 >10,000ex) polyethylene (PE)repeating unit = 28 g/molpolypropylene (PP)repeating unit=42g/molpolystyrene (PS)repeating unit=104g/mol1-2. Classification of polymersPlastics - PVC, PE, PS, PC etcPolymerFiber - nylon-6, nylon-66, PET etcElastomer- polybutadiene, SBR etc1-3. Structure 에 따른 분류i) Thermoplastic(열가소성)- 열을 가했을 때 flow가 일어남.ex) PS, PE, PP, Nylon, PET etcii) Thermosetting(열경화성) - 열을 가하면 경화 반응이 일어남. 일단 경화 후에는 flow가 일어나지 않고 계속해서 열을 가하면 degradation 일어남.ex) epoxy 수지, phenol 수지, 불포화 polyester 수지 etc1-4. Grade 에 따른 분류i) Commodity plastic (범용 plastics)ex) PS, PE, PP, PVC특징 a) easy processibilityb) softc) excellent electrical resistanced) stable in low temp, not in boiling watere) low priceii) Engineering plasticsex) Nylon, PET, Polycarbonate (PC), PBT, Poly (oxy methylene) (POM),혹은 Polyacetal, Polypropylene oxide + PS Noryl(blend).특징 a) good heat stabilityb) good impact strengthc) good mechanical propertiesd) price is 2 or 3 times higher than commodity plasticsiii) Specialty polymersex) poly (ether ether ketone) (PEEK), polyimide, liquid crystalline polymer(LCP), polysulfone, etc.특징 a) high temp. stability, Tg > 100 oCb) high modulusc) high pricePEEKtrade name : Victrex PEEK, by ICITg = 143-150 C , Tm = 334-340 CPolyimidePolyimide 2080Where R is (20%)or (80%)Tg = 305 CPolyimide (PI)upper service temp.300-350 CPolyamide-imide (PAI)215-350 CPolyetherimide (PET) – ultem200C: thermal expansion coeff.: the linear expansion coeff.Liquid crystalline Polymer (LCP)thermotropic LCD – 열방성 액정 고분자, 열을 가하여 crystal-to-nematic transition 후에 액정 상태를 나타내는 고분자ex) Hoechst-celanese 의 Vectra A900:-HBA HNA(hydroxy benzoic acid) 6-hydroxy-2-naphthoic-acid73 mol% 27mol%이외에도 Du Pont, Eastman Kodak 및 Amoco 에서 생산됨.ii) lyotropic LCP-액체 즉 용액상태에서 액정현상을 나타내는 고분자ex) Du-pont 의 Kevlarhigh modulus fiber (106kg/cm2)a. ordered smectic 구조a'. unordered smectic 구조b. nematic구조c. cholesteric 구조d. discotic 구조