Polybutadiene, impact modifier

To overcome the brittleness of GPPS, the material was modified by incorporation of polybutadiene. Impact-modified polystyrene (IPS) was invented by Ostromislensky [1] and has been commercialized since the 1950s. IPS consists of a polystyrene matrix with embedded cellular rubber particles. By rubber... 

Bert Klumperman was bom on 23 September 1962 in Hellgendoom, the Netherlands. After secondary school, he studied chemical engineering at the University ofTwente (Enschede, the Netherlands). He graduated in 1985 for his MSc under the supervision of Prof A. Bantjes on a biomedical topic. Immediately after that, he started to work at DSM Research (Geleen, The Netherlands) as a research associate. After an initial 2 years of research on polybutadiene impact-modified poly (styrene-co-acrylonitrile) (ABS), he became the responsible person for polymer chemistry research on STY-MAnh copolymers. 

Buna CB, Polybutadiene impact modifier, Bayer Corp., Fibers, Additives Rubber Div. 

System uses polybutadiene impact modifier, which, due to the presence of double bonds, is less UV stable than other components of the system. For this reason, exposure of material to direct sunlight, for extended periods of time, shovdd be avoided. 

Water, methanol, and n-hexane do not influence the photooxidation of PVC (43), but the photodegradation is accelerated by ferric chloride (70,71) and certain other compounds containing iron (70,71,72). Purification of the polymer might be expected to enhance its photostability by removing deleterious impurities such as iron compounds that are derived from metal equipment. This type of result was obtained in one recent study (58) but not in others (30,59). In contrast, the photo-oxidative degradation of PVC should be enhanced by admixture of the polymer with materials that are unusually susceptible to photooxidation themselves. Such behavior has been observed for impact-modified PVC containing polybutadiene-based polyblends (69,73). 

Transparency is often required. This is achieved by arranging that the particle size of the modifier to be below that of the wavelength of visible light (0.4-0.8 pm). This can normally be achieved by emulsion polymerisation, e.g., polybutadiene, polystyrene. Adhesion and surface compatibility between the polymer and modifier can be achieved by surface grafting of polar groups, e.g., acrylonitrile, various acrylates, onto the impact modifier surface before blending. 

Impact modifiers Polybutadiene rubber, methacrylate-butadiene-styrene terpolymers, acrylic rubber... 

SEM and transmission electron microscopy (TEM) are employed to examine materials for the presence and distribution of impact modifiers such as polybutadiene rubber in high impact polystyrene (HIPS) and methacrylate butadiene styrene terpolymer in PVC. Quantification is either by transmission IR spectroscopy against standards or nuclear magnetic resonance (NMR) spectroscopy. 

DMTA is a very interesting tool for characterizing heterogeneous materials in which domains of distinct Tg values coexist. The most interesting cases involve modified thermosets of different types (see Chapter 8). Examples are the use of rubbers (e.g., liquid polybutadiene and random copolymers), or thermoplastics (e.g., polyethersulphone or polyetherimide in epoxy matrices or poly(vinyl acetate) in unsaturated polyesters), as impact modifier (epoxies), or low-profile additives (polyesters). The modifier-rich phase may be characterized by the presence of a new a peak (Fig. 11.10). But on occasions there may be superposition of peaks and the presence of the modifier cannot be easily detected by these techniques. If part of the added polymer is soluble in the thermoset matrix, its eventual plasticizing effect can be determined from the corresponding matrix Tg depletion, and the... 

Polybutadiene made by alkyllithium initiators is essentially free of the gel and color sometimes associated with the transition-metal catalysts and thus occupies a large market as an impact modifier in plastics. 

JSR Corp. Polybutadiene-cislow(LCBR) Butadiene High productivity LCBR as impact modifier for plastics such as PS 1 1987... 

Initially various rubbery butadiene and styrene-butadiene block polymers were screened as impact-modifying agents for polystyrene. Commercial polystyrene and various rubbers were blended by dissolving the polymers in benzene and by subsequently precipitating them with isopropyl alcohol. The solid polymer blends were dried and molded into test bars. Laboratory and commercial polybutadiene and polystyrene were used in several combinations with the block polymer prepared in our laboratory. 

From its architecture, ASA is closely related to ABS however, instead of polybutadiene rubber particles grafted with poly(styrene-acrylonitrile) (PSAN), poly(alkyl acrylate)-based graft rubber particles are used as the impact modifier (Figure 16.1). 

The use of core-shell impact modifiers combined with styrene-hydrogenated poly butadiene block copolymers in sPS is described by Rohm and Haas [24]. The core of the former type is of polybutadiene or its copolymer, the shell consists predominately of polystyrene. Rohm and Haas found that a synergistic effect is present and that the Izod notched impact strength is higher when both rubber types are used instead of only one. 

By means of a coupling agent, i.e., SiCU, it is possible to produce a polybutadiene with a branched, starlike configuration, which leads to excellent processability [87], Whereas these coupled polymers are used in tire production, those with narrow molecular weight distributions occupy a large market as impact modifiers in plastics. 

Although impact modifiers have been investigated since the birth of the rubber-modified plastics industry, they still remain an active area of investigation. The earlier impact polymers were modified with polybutadiene and polvstyrene-co-butadiene made via emulsion polymerization. As the industry matured, "solution" polybutadiene and to a minor extent styrene/butadiene block... 

Taktene. [Polysar] Sol n. polybutadiene f(X tires, footwear, belting, hose, floor die, gdf ball centers, molded and ex-tru d goods, mast atches impact modifier. 

Styrene-acrylonitrile copolymer (SAN) and its impact modified versions, viz., ABS (polybutadiene rubber grafted SAN), ASA (acrylate rubber grafted SAN), AES (EPDM rubber grafted SAN)... 

Because of its inherent brittleness, polystyrene homopolymer itself has limited application in blends. However, its impact modified version, viz., HIPS, is more widely used. HIPS itself is a reactor-made multiphase system with 5 to 13% polybutadiene ( cis -rich) dispersed as discrete particles in the polystyrene phase, with an optimum particle size of mean diameter of 2.5 fim. The rubber in HIPS is chemically grafted to some extent to the polystyrene. The effective volume of... 

In order to improve both the thickness sensitivity and low temperature sensitivity of the impact strength, polycarbonate has been blended with a variety of low T, elastomeric impact modifiers. More important among these are the core-shell rubbers like PMMA-g-polybutadiene, PMMA-g-SBR (MBS), PMMA-g-n-butylacrylate (acrylic core-shell), all normally composed of 0.1/core particles. These modifiers improve both the thick-section (6.4 mm) and low temperature notched Izod impact properties of polycarbonate [Witman, 1981 Neuray and Ott, 1981 Bussink et al., 1977] (Figures 15.13 and 15.14). The blends are of course opaque. Impact modified polycarbonate also shows better retention of impact strength with heat-aging. 

SMA PC blend. This blend (Arloy , Arco) contained SMA grafted with polybutadiene as the impact modifier. The properties of SMA/PC blend were similar to ABS/PC blend with slightly higher heat distortion temperatures (107 to 117°C) but comparable impact strength (> 500 J/m). However, it was discontinued from the market due to unfavorable economics relative to ABS/PC blend. The partial miscibility between the styrene-maleic anhydride and polycarbonate accounts for the adequate compatibility of this blend as evidenced by the high level of tensile and impact strengths. 

All the commercial PBT/PC and PET/PC blends also contain typically 10-20 wt% of an additional elastomeric impact modifier. The exact nature and the content of the impact modifier is kept proprietary and often forms the basis for a particular blend patent. Typically core-shell rubbers such as polymethylmethacrylate grafted butadiene-styrene rubber (MBS) or an all acrylic core-shell rubber such as poly (MMA-g-n-BuA) are used [Nakamura, 1975 Chung, 1985]. ABS (with high polybutadiene content S 50%) or ASA... 

Proprietary compatibilizers-cwm-impact modifiers offer a more economic solution and are widely used. These materials are formulated for specific types of polymer mixtures, viz. Blendex — polybutadiene-type compatibilizer for styren-ics, PVC, TPU, PET, EXL — an acrylic-based additive for PEST, Fusabond — maleated-PO compatibilizer for PO/PET blends, Vector — is SBS-type block copolymers with stabilizers, designed for PO/PS commingled mixtures, etc. 

Elastomers or rubbers are flexible materials that are mainly used in tires, hoses, and seals as adhesives or as impact modifiers of thermoplastics. They exhibit high resistance to impact, even at low temperatures at which materials increase their rigidity. Eor some of the applications (e.g., tires or hoses), these materials have to be slightly crosslinked once they are formed into the desired shape in order to impart them dimensional stability, since otherwise they tend to slowly flow. Elastomers are polymers that are used above their glass-transition temperature (Tg). Some examples of common elastomers are polybutadiene, which is used as an impact modifier of rigid plastics SBR (copolymer of styrene and butadiene), mainly used in tires EPDM (copolymer of ethylene, propylene, and a diene monomer, usually norbornene) NBR (copolymer of acrylonitrile and butadiene) and so on. 

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