ISSN:0730-6679    

DOI:10.1002/adv.1992.060110401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractPolymer blends with enhanced properties and processability for specific applications are modified through the incorporation of a variety of additives. The performance of these additives is often difficult to predict from considerations of their known behavior in the separate blend constituents. This overview article discusses additives and modifiers in terms of types and specific functions (e.g., impact modifiers, compatibilizers, flame retardants, stabilizers) and provides an analysis of the possible effects of their repartition in the constituent phases and at the interface. © 1992 John Wiley&Sons, Inc

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractBlending of immiscible polymers offers attractive opportunities for developing new materials with useful combinations of properties. However, simple blends often have poor mechanical properties and unstable morphologies. Compatibilization of such blends is necessary. Preformed graft or block copolymers have been traditionally added to act as compatibilizers. Another route, however, is to generate these copolymer compatibilizers in situ during melt blending using functionalized polymers. In this review, a variety of reactive polymers that have been utilized in the reactive compatibilization of polymer blends is examined. They are classified into six major categories according to the types of reactive groups they have, namely, maleic anhydride, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl and epoxide, and reactive groups capable of ionic bonding. Their preparation methods and applications and the chemical reactions they undergo during melt blending are presented. © 1992 John Wiley&Sons, Inc

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractSimple blends of poly(2,6 dimethyl 1,4‐phenylene ether) (PPE) and polypropylene (PP) are highly incompatible and consequently quite brittle regardless of the molecular weights and ductility of the individual components. Hydrogenated, styrene‐diene block copolymers, viz. S‐EB‐S triblock and S–EP diblock copolymers, can be used to compatibilize and toughen the blends. The ductility and impact toughness of the PPE–PP blends depend not only upon the nature of styrene block copolymers but also on the nature of PPE and PP used. It was found that lower‐molecular‐weight PPE was actually better in achieving a blend with desired combination of high‐impact toughness and high heat distortion temperature. Compatibilization efficiency and morphological considerations influencing the blend's properties are discussed. © 1992 Jo

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this article, we present a newly discovered polymerization process, called the freeradical retrograde‐precipitation polymerization (FRRPP) process, that is shown to have certain desirable features not normally found in free‐radical polymerization processes. Here, free radical polymerization occurs with an unusual but widely applicable polymer precipitation phenomenon. Local heating is observed in the vicinity of the radical sites, which results in the controlled rate of propagation with a decrease in the rate of radical–radical termination reactions. In the case experiments, the existence of hot spots in the reactor fluid is shown to occur. There is also evidence of slowdown of the growth of polymer radicals after initiator decomposition. The polymer radicals, shown to have a relatively narrow molecular weight distribution, continue to grow at a controlled rate long after all the initiator molecules have decomposed. The addition of a second monomer results in the formation of a thermoplastic elastomer triblock copolymer. © 1992 John Wiley&Son

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractReactive compounding is continuously emerging as a novel processing technique to modify existing polymer systems and improve performance/properties. The essential elements of control over the internal pressure and temperature combined with understanding of the chemistry and process equipment brings optimal results. Today's role of contract manufacturer is not only to provide the facilities and hardware but also the understanding of process technology to help develop new products in the most economic and timely fashion. © 1992 John Wiley&Sons, Inc

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractBlends of high viscosity polypropylene (PP) and low viscosity low density polyethylene (LDPE) were prepared in the Brabender batch intensive mixer. The rheological mismatch of these immiscible blend components resulted in coarse blend morphologies and poor mechanical properties. By reacting these blends with 1800 ppm Lupersol 101 peroxide at 180°C, the morphology became much finer and, at 50/50 weight ratio, assumed co‐continuous phase structure. As a result, the mechanical properties improved significantly. The above observations are attributable to the fact that the peroxide reaction at this level of concentration removes the rheological disparity of the blend components, a condition that is more favorable for efficient dispersive mixing. It has been frequently stated that the scale and uniformity of dispersive mixing affects the uniformity and controllability of reactions occuring in molten blends. This work shows, for the first time, that reactions with peroxides alter the blend morphology in a beneficial manner. The two phenomena are, therefore, mutually dependent. © 1992 John Wiley&Sons,

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis is the first part of a survey of developments reported in the open literature during 1991 on the subject of injection molding of fiber‐reinforced thermoplastics. Topics discussed include materials, polymers, reinforcing fibers and composite properties, advances in the injection molding process, fiber breakage, shrinkage, and warpage, as well as alternatives to the injection molding process. © 1992 John Wiley&Sons, I

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1992.060110409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY