摘要:

A bifunctional living poly(dimethylsiloxane), poly(DMS), was prepared through the anionic ring-opening polymerization of hexamethyl-cyclotrisiloxane (D3) with dilithium salt(2)of bis(p-hydroxydimethylsilyl)phenyl ether(1)as an initiator. The subsequent termination reaction with dimethylchlorosilane followed by the hydrosilation reaction of the end-standing silane function with allyl alcohol produced the uniform-size poly(DMS) with a hydroxypropyl group at both chain ends(4).The polyurethane/polysiloxane block copolymer having uniform-size poly(DMS) segments was then synthesized through the polyaddition reaction of the poly(DMS) having hydroxypropyl groups at both ends(4)with 4,4′-diphenylmethanediisocyanate followed by chain extension with 1,4-butanediol.

ISSN:0360-2559    

DOI:10.1080/03602558908048589

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

“Reactive extrusion processing” is a catch phrase of the 1980s to cover an increasingly important operation in polymer manufacturing. An acceptable definition would be “chain building or alteration during extrusion.”

ISSN:0360-2559    

DOI:10.1080/03602558908048590

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Styrenic polymers can be produced by many techniques, but relatively few have proven successful on a commercial scale. In recent years, the so-called bulk, continuous process has dominated industrial production and has largely replaced competitive routes such as suspension and emulsion. It is now used for most molding and extrusion grades of crystal polystyrene, for rubber- modified polystyrene, for styrene-acrylonitrile copolymer, and for certain varieties of ABS. The historic definition of “bulk” supposed use of the neat, undiluted monomers, but more recent terminology follows industrial practice in allowing substantial amounts of solvents (e.g., ethylbenzene) as chain- transfer agents and processing aids [l].

ISSN:0360-2559    

DOI:10.1080/03602558908048591

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A mathematical model based on a slab configuration is employed to simulate fast step growth polymerizations. The effect of mixing pattern, molecular diffusivity, and catalyst concentration on the conversion profile is studied for reaction systems with different gel conversions. The results, which can be explained by the intensity and the scale of segregation, provide some conceptual guidelines in designing appropriate mixing methods for fast step growth polymerizations. The distribution of slab thickness and the benefit of using cascade impingement mixing in the reaction injection molding (RIM) process are explained by the phenomenon of flow transformation in the mixing chamber.

ISSN:0360-2559    

DOI:10.1080/03602558908048592

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Since the introduction of ethylene propylene elastomers over 25 years ago, their importance has grown almost exponentially and, today, EPDM is used in a wide range of applications. The spectacular growth of EPDM is quantified by an average growth rate (over the last 10 years) of around 11% per annum. EPDM ranks third among the synthetic rubbers in importance, immediately after SBR and BR. This progression can be attributed to its unique end-use performance in highly filled rubber applications, along with excellent ozone and weathering resistance.

ISSN:0360-2559    

DOI:10.1080/03602558908048593

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

To modify the surface of carbon fiber, the anionic grafting of polyesters from potassium carboxylate (COOK) groups on the surface was investigated. The COOK groups were introduced onto the surface of carbon fiber by the reaction of carboxyl groups (introduced by the oxidation of the surface with nitric acid) with potassium hydroxide. Untreated carbon fiber has no ability to initiate the anionic ring-opening copolymerization of epoxides with cyclic acid anhydrides. On the contrary, the anionic ring-opening copolymerization of epoxides—such as styrene oxide (SO), chloromethyloxirane (ECH), and glycidyl phenyl ether (GPE)—with cyclic acid anhydrides—such as maleic anhydride (MAn), succinic anhydride (SAn), and phthalic anhydride (PAn)—was found to be initiated by the COOK groups on the surface. In the polymerizations, alternating copolymers (i.e., polyesters) were effectively grafted from the carbon fiber surfaces depending on the propagation of the polymer from the surface COOK groups: for example, when the copolymerization of ECH with PAn was carried out at 120 °C by use of COOK groups on carbon fiber as catalyst, the percentage of grafting of the polyester reached as much as 40%. The intrinsic viscosity of ungrafted polyester obtained from this polymerization was determined to be 6 cm3/g (chloroform, 30.0 °C). The initiating ability of carbon fiber increased with an increase in the content of COOK groups. Furthermore, the addition of 18-crown-6 was found to be effective for the increase of the copolymerization rate and for the percentage of grafting of polyester on the surface.

ISSN:0360-2559    

DOI:10.1080/03602558908048594

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0360-2559    

DOI:10.1080/03602558908048595

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:0360-2559    

DOI:10.1080/03602558908048596

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0360-2559    

DOI:10.1080/03602558908048588

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor