Abstract: A conjugated diene/monovinyl substituted aromatic hydrocarbon copolymer is stabilized by the addition of a complex acrylate, in combination with at least one of an alkyl thiopropionate, an organic phosphite and a non-acrylate substituted hindered phenolic compound.

Abstract: Sequential charging of initiator and monomers in a multistage solution polymerization process involving conjugated diene and monovinylaromatic monomers wherein the initial and final charges are monovinylaromatic monomer results in the production of polymodal linear block copolymers with terminal resinous blocks. A typical 6-stage charge sequence is as follows: stage 1: (S.sub.i); stage 2: (S.sub.i); stage 3: (B); stage 4: (S.sub.i); stage 5: (B) and stage 6: (S) wherein (S.sub.i) is monovinylaromatic monomer and initiator, (B) is conjugated diene monomer and (S) is monovinylaromatic monomer. At each stage, polymerization is allowed to continue until no free monomer is present.The polymodal block copolymer products comprise high, medium and low molecular weight species designated, respectively, as S.sub.1 -S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 -S.sub.4 ; S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 -S.sub.4 ; and S.sub.3 -B.sub.2 -S.sub.4 wherein S.sub.1, S.sub.2, S.sub.3 and S.sub.

Abstract: Sequential charging of initiator and monomers in a multistage solution polymerization process involving conjugated diene and monovinylaromatic monomers wherein the final charge is a mixture of these monomers results in the production of resinous polymodal linear block copolymers each with a terminal tapered block. A typical 5-stage charge sequence is as follows: Stage 1: (S.sub.i); Stage 2: (S.sub.i); Stage 3: (B); Stage 4: (S.sub.i); Stage 5: (S+B) wherein (S.sub.i) is monovinylaromatic monomer and initiator; (B) is conjugated diene monomer and (S+B) is monovinylaromatic monomer and conjugated diene monomer. At each stage, polymerization is allowed to continue until no free monomer is present.The trimodal block copolymer products comprise high, medium and low molecular weight species designated, respectively, as S.sub.1 -S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 .fwdarw.S.sub.4 ; S.sub.2 -B.sub.1 -S.sub.3 -B.sub.2 .fwdarw.S.sub.4 ; and S.sub.3 -B.sub.2 .fwdarw.S.sub.4 wherein S.sub.1, S.sub.2 and S.sub.

Abstract: Resinous polymodal block copolymers of such as butadiene and styrene which are craze-resistant, transparent, and substantially color-free, and methods of producing the block copolymers. The copolymers are prepared by sequential charge copolymerization modes comprising the solution polymerization of at least two charges each of a conjugated diene, a monovinylarene, and a monoalkali metal initiator, at least one charge of conjugated diene monomer precedes the last charge of monoalkali metal initiator, at least one charge each of monovinylarene and of conjugated diene follows the last charge of monoalkali metal initiator, and the final charge of monomer is a charge of conjugated diene monomer, such that the number of charges of each of said components is not more than three, and the total of the charges of the three components is 8 or 9.

Abstract: A blend comprising (1) 20 to 70 weight percent of a styrene polymer, and (2) 30 to 80 weight percent of a resinous copolymer having a polymerized monovinyl-substituted aromatic compound block and a polymerized monovinyl-substituted aromatic compound/conjugated diene random copolymer block. Such blends have been found to possess outstanding toughness and excellent clarity.

Abstract: A catalyst composition of a chromium compound supported on a silica-containing substrate is prepared by contacting the silica-containing substrate with a gaseous carrier containing water vapor at a temperature in the range above about 1100.degree. F. to about 2000.degree. F. for a time sufficient to effect a broadening of molecular weight distribution of polymers produced using the catalyst. In further embodiments, the catalyst prepared by the method described above and a method for preparing polymers of ethylene using the catalyst prepared by the method described above.

Abstract: A thermally stable resinous block terpolymer is formed by first polymerizing styrene to form a resinous block segment, thereafter forming a block segment of sequentially polymerized isoprene and 1,3-butadiene, and finally coupling the resulting polymer chains with a polyfunctional coupling agent.

Abstract: A conjugated diene/monovinyl-substituted aromatic compound resinous copolymer such as a styrene/butadiene block copolymer is produced using two additions of the monovinyl-substituted aromatic component and initiator in a manner such that the product has 71 to 81 wt. percent monovinyl-substituted aromatic component and has a ratio based on the number average molecular weight of monovinyl-substituted aromatic component blocks in first and second polymer chains thus produced prior to coupling within the range of 3 to 7. The final product resulting from coupling such polymers has long integral hinge flex life and high hardness. This is accomplished by using no more than 5 millimoles of initiator per mole of monomer in the second addition.

Abstract: The effluent from a lithium initiated polmerization, wherein a coupling agent is utilized to join two or more polymer molecules together, with the resulting generation of LiO--, LiS--, or ##EQU1## groups is treated with carbon dioxide and an excess of water and thereafter stabilized with an organic phosphite and a glycine in combination with a hindered phenol.