Natural Rubber Synthetic Rubbers Thermoplastic Elastomer TPE Rubber

������� �� • ������ (Natural Rubber( • ������� (Synthetic Rubbers ( • Thermoplastic Elastomer (TPE) Rubber : Tg ��� Tm < 25 o. C 1

�������� (NR( 1 2 3 4 CH 2=C–CH=CH 2 CH 3 C 5 H 8 CH 2 C=C CH 3 H o. C T = -70 g cis-1, 4 -polyisoprene 99% ~���� cis ����� (������� ) ����� stere ��� cis ������ 97 -98 % (Synthetic cis-1, 4 -polyisoprene) 4

������� Synthetic Rubbers • • )Synthetic) Polyisoprene Polybutadiene ���� Butadiene Rubber (BR( Styrene-Butadiene Rubber (SBR( Nitrile-Butadiene Rubber (NBR) ���� Nitrile Rubber Polychloroprene ���� Chloroprene Rubber (CR) Butyl Rubber Thermoplastic Elastomers (TPE) 7

1. Polyisoprene • ��������� cis-1, 4 -Polyisoprene ������ stereospecific catalyst – Coordination catalyst of trialkyl Aluminum + Ti. Cl 4 (Al-Ti) – Coordination catalyst of alane (Al-hydride derivative) + Ti. Cl 4 – Lithium alkyl (Li+R-) • Isoprene monomer (C 5 H 8) ����� 2 ��� ���������� (addition) ��� 4 ������ cis-1, 4 trans-1, 4 vinyl 1, 2 ��� 8

. 2 Polybutadiene (Butadiene Rubber, BR( • ���� homopolymer ��� Butadiene (C 4 H 6( CH 2 = CH - CH = CH 2 ---> -CH 2 - CH = CH- CH 21, 4 -addition • �� Tg ��������� (-100 o. C) ����� 1. ����������� ��� (good abrasion resistance) 2. 10 ���������

12

• Alkali Metal • R 2 Al. Cl-Co + benzene ��� > 99% cis 13

. 3 Styrene Butadiene Rubber (SBR( • ��������� • ���� copolymer ��� styrene CH 2=CH(C 6 H 5) ��� butadiene CH 2 = CH - CH = CH 2 – Polystyrene �� Tg = 100 o. C (plastic) – Polybutadiene �� Tg = -100 o. C (rubber) • ������� Copolymer ��������� 14 ��������� �

. 4 Nitrile-Butadiene Rubber (NBR) ���� Nitrile Rubber • ���� copolymer ��� Acrylonitrile ��� Butadiene CH 2 = CH + CH 2 = CH - CH = CH 2 CN CH 2 -CH-CH 2 -CH=CH-CH 2 CN • ������� �� ��� CN 15 -50% 16

5. Polychloroprene (Chloroprene Rubber, Neoprene) • ���� homopolymer ��� 2 -chloro-1, 3 -butadiene CH 2 = C-CH = CH 2 Cl • ���� isoprene ����� methyl group ���� Cl atom (���� butadiene ����� H atom ���� Cl atom) • �� �������� Cl => ����� oil 18

. 6 Isobutylene-Isoprene Rubber (IIR) ���� Butyl Rubber • ���� copolymer ��� 97 -99% isobutylene ��� 1 -3 % CHisoprene CH 3 3 CH 3 C = CH 2 + CH 2=C-CH=CH 2 CH 3 2 -CH 2 -C=CH-CH 2 -C-CH • ����� double bond 1 ����� isoprene ������ crosslinking • ������ isoprene ������ Butyl 19

IIR (��� ( • �������� IIR ���� Butyl Rubber ��� – low rate of gas permeability (10% ��� NR) – thermal stability – chemical and moisture resistance • ���������� �� �������� 20

. 7 Thermoplastic Elastomer (TPE) • Elastomer ��� Rubber ������ vulcanized ���� crosslinked • Polymer ������ crosslinked ���� thermoset • Thermoplastic Elastomer ������ physical crosslink ������ chemical crosslink • ������ physical crosslink ���� 23 ���������

���� TPE • ����� TPE ���� triblock copolymer ��� A-B-A ���� SBS (Styrene-Butadiene-Styrene) ��� – Polystyrene ���� hard domain (������� )���� physical crosslink ����� plastic ��� 25 o. C (�� Tg = 100 o. C) – Polybutadiene ���� flexible chain (Tg = -100 o. C) 25

Phase Separation of SBS PS = Physical crosslink (���� ) PB = Rubbery phase (��� ( 26