摘要
以CD_3COCD_3为溶剂,对室温下测定的氟硅橡胶、乙烯基氟硅橡胶、二甲基硅氧烷氟硅橡胶、亚苯基氟硅橡胶和乙烯基亚苯基氟硅橡胶等试样的~1H-NMR谱进行了归属,并由峰面积分别计算了橡胶的组成和平均分子量。以乙烯基氟硅橡胶为例,其乙烯基含量的测定值与实际值之间的平均误差为±0.0004。
The mierostructure of a series of fluorosilicone rubbers were characterized by 1H-NMR spectroscopy , by using CD3COCD3 as solvent. The methods for calculating the composition and molecular weight of these fluorosilicone elastomers were also developed .For polymethyl γ-trifluoropropyl siloxane ,For the copolymer of methyl y-trifluoropropyl siloxane (A) and methyl vinyl siloxane (B), -[(CH3 )Si( C2CF3)O]-m[(CH3 )Si( CH=CH2 )O]n, δCH=CH2 6.00 ppm , the molar ratio of the two components n/m is given bySCH=CH2 and SCH2 is peak areas of - CH=CH2 and CH2, respectively . The erro in this method is ±0.0004.For the copolymer ended by (CH3)3Si- , the polymerization degree of the two components , n and m , and the average molecular weight M is given byFor the copolymer ended by CH2=CHSi--(CH3)2-For the copolymer of (A) and dimethyl siloxane(C),[-(CH3) Si(C2H4CF3)]m[(CH3)2SiO]n, δCH3(C)0.14 , 0.7 ppm ,n/m is given byFor the tripolymer of (A) ,(B) and (C), [-(CH3) Si(C2H4CF3)O]m[(CH3)2SiO]n[(CH3)-Si(CH-CH2)O]p,n/m and p/m can be calculated by eq . 8 and 1, respectively .For the copolymer of (A) and paraphenylene-bis (methyl γ-trifluoropropyl siloxane) (D), HO[-(CH3) Si (C2H4CF3)O]m[(CH3)Si-(C2H4CF3)(CH3)Si(C2H4CF3)O]nH, δCH3(D) 0.54 ppm ,δCH2(-si) 1.16 ppm ,δCH2(-CF3)(D) 2.19 ppm , δC6H4 7.70 ppm , n/m is given by n/m=5CH2(D)/2SCH2(A) (9)For the tripolymer of (A), (B) and (D), CH=CH2 is sited on the end of molecular chain , which is confirmed by PRFT - NMR technique . The molar fraction of ended group CH2=CH ( CH3)2 SiO- ,p ,is given by m/n/p = SCH2(A)/0.5SCH2(D)/(SCH=CH2/3) (10)
出处
《合成橡胶工业》
CAS
CSCD
北大核心
1992年第4期231-234,共4页
China Synthetic Rubber Industry
关键词
核磁共振
波谱法
氟硅橡胶
橡胶
nuclear magnetic resonance spectroscopy
fluorosilicone rubber
compo- sition
molecular weight
