| 摘要 |
#CMT# #/CMT# New block elastomers comprise at least two linear polydiene branches that are joined together at one end by a silicon-, tin-, germanium-, lead- or phosphorus-containing group derived from a coupling agent or by a group derived from a nonpolymerizable polyfunctional electrophilic coupling agent and have at least two linear polydiene grafts at their other ends. #CMT# : #/CMT# Independent claims are also included for: (1) producing block elastomers by synthesizing a macromonomer by reacting a carbanion-containing living diene polymer with a stoichiometric excess of a compound (I) having an anionically polymerizable group and group susceptible to nucleophilic substitution by the carbanion; reacting the macromonomer with a nucleophilic initiator to obtain a living polymacromonomer; reacting the living polymacromonomer with a C4-C12 conjugated diene monomer to obtain a living polymacromonomer-polydiene diblock copolymer; and reacting to copolymer with a nonpolymerizable polyfunctional electrophilic coupling agent, a functional group precursor electrophilic reagent or a protonic acid donor; (2) diene polymacromonomer produced by reacting a living polymacromonomer as above with a functional group precursor electrophilic reagent or a protonic acid donor; (3) rubber composition usful for making tires, comprising a block elastomer as above and a reinforcing filler; (4) finished or semifinished article for the ground-contacting system of an automobile, comprising a rubber composition as above. #CMT#USE : #/CMT# Rubber compositions containing the block elastomers are useful for pneumatic tire manufacture. #CMT#ADVANTAGE : #/CMT# Rubber compositions containing the block elastomers have increased hysteresis, giving tires with better roadholding and comfort. #CMT#POLYMERS : #/CMT# Preferred Elastomers: There are two branches with 2-25 grafts at the end of each branch. The other end has an electrophilic function, especially carboxylic acid, alcohol, amine, silanol, alkoxysilane or organostannyl, or a proton. The grafts comprise (co)polymers of butadiene and/or isoprene. The branches are 10-100 times longer than the grafts The number-average molecular weight (M n) of the branches is 50000-300000. The M n of the grafts is 5000-25000. Preferred Process: (I) is chloromethylstyrene, chlorodimethylsilylstyrene, chlorodimethylsilylmethylstyrene or bromomethylstyrene and is used in a 0.05-0.5 molar excess. The reaction temperature in the first step is -10 to 5[deg]C. The nucleophilic initiator is s-, n- or t-butyl lithium, naphthyl sodium, 1,4-disodio-1,1,4,4-tetraphenylbutane, diphenylmethyl potassium or sodium, methylstyryl lithium, 1,1-diphenyl-3-methylpentyl lithium or an amine-, imine-, tin- or alcohol-functional initiator. The coupling agent is dichlorodimethylsilane. The functional group precursor electrophilic reagent is a carboxylic acid, alcohol, silanol, alkoxysilane or organostannyl precursor. The acid donor is methanol. |
