Elastomer-Modified Polypropylene

In the early history of polypropylene technology, blends with ethylene propylene copolymer were introduced for toughening polypropylene. Subsequently block copolymers of polypropylene with random ethylene propylene copolymer rubber were produced in the polymerization reaction. Dynamic vulcanization of ethylene propylene terpolymer in blends with polypropylene together with hydrocarbon oils was a third technology. The first TPO was elastomer (ethylene)-modified propylene (EP polymer) marketed to overcome polypropylene s weakness that cold temperature negatively impacts resistance. 

Subsequently, there are also TPOs made from butyl-type elastomers such as butyl modified polypropylene, butyl-low-density polyethylene (LDPE), and butyl-high-density polyethylene (HDPE), as well as EP elastomer and various polyethylenes. One distinctive incident of filler addition to a PP-EP-elastomer-based TPO is that the filler preferentially goes onto the elastomer phase of the blend. Thus, the addition of filler to a TPO actually lowers the flexural modulus. 

The advantages of block copolymer of butadiene and styrene are high coefficient of friction, good elasticity, broad hardness range, no need for vulcanization, good color and colorability. 

Other additives compatibiKzers (a-methyl styrene), ester of resins (polyindene, coumarone-indene, pentaerythritol ester of hydrogenated rosin) stabilizers (zinc dibutyl dithio carbamate) 

TPEs of SBS (and SEBS)-type are versatile. Compared to PVC compounds, ester plasticizers cannot be used in TPE compounds. Vulcanizing agents such as accelerators, sulfur, or peroxides are not required in SBS-type TPE block copolymers. EPDM is blended with SBS to increase ozone resistance. PS, polyethylene (LDPE, LLDPE, HDPE), and polypropylene (PP) are used as additive polymers with SBS and SEBS. Polystyrene (PS) is compatible with B-S block copolymers. Polystyrene is useful to adjust properties and cost of SBS compounds. The addition of polystyrene into SBS increases hardness, modulus, tensile strength, tear strength, and abrasion resistance. Styrenic resin (a-methyl styrene) can be used as a blend with PS or as an alternative for SBS compound. This resin can be used as a blend with polystyrene as an alternative. Styrenic resin enhances flow properties and physical properties. It is more compatible compared to polystyrene and assists in adhesion and coherent processing. 

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ABA ABS ABS-PC ABS-PVC ACM ACS AES AMMA AN APET APP ASA BR BS CA CAB CAP CN CP CPE CPET CPP CPVC CR CTA DAM DAP DMT ECTFE EEA EMA EMAA EMAC EMPP EnBA EP EPM ESI EVA(C) EVOH FEP HDI HDPE HIPS HMDI IPI LDPE LLDPE MBS Acrylonitrile-butadiene-acrylate Acrylonitrile-butadiene-styrene copolymer Acrylonitrile-butadiene-styrene-polycarbonate alloy Acrylonitrile-butadiene-styrene-poly(vinyl chloride) alloy Acrylic acid ester rubber Acrylonitrile-chlorinated pe-styrene Acrylonitrile-ethylene-propylene-styrene Acrylonitrile-methyl methacrylate Acrylonitrile Amorphous polyethylene terephthalate Atactic polypropylene Acrylic-styrene-acrylonitrile Butadiene rubber Butadiene styrene rubber Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cellulose nitrate Cellulose propionate Chlorinated polyethylene Crystalline polyethylene terephthalate Cast polypropylene Chlorinated polyvinyl chloride Chloroprene rubber Cellulose triacetate Diallyl maleate Diallyl phthalate Terephthalic acid, dimethyl ester Ethylene-chlorotrifluoroethylene copolymer Ethylene-ethyl acrylate Ethylene-methyl acrylate Ethylene methacrylic acid Ethylene-methyl acrylate copolymer Elastomer modified polypropylene Ethylene normal butyl acrylate Epoxy resin, also ethylene-propylene Ethylene-propylene rubber Ethylene-styrene copolymers Polyethylene-vinyl acetate Polyethylene-vinyl alcohol copolymers Fluorinated ethylene-propylene copolymers Hexamethylene diisocyanate High-density polyethylene High-impact polystyrene Diisocyanato dicyclohexylmethane Isophorone diisocyanate Low-density polyethylene Linear low-density polyethylene Methacrylate-butadiene-styrene... 

EMPP elastomer modified polypropylene ESU electrostatic unit... 

In this temperature range, the viscosities of the two components are very similar and the mechanical shear can be effectively transferred to the mixture to enforce a good dispersion of the phases. Intensive mixing and high homogeneization levels are especially important when, for quality reasons, the modifying capability of the elastomer has to be optimized. This is the case, for instance, of the new family of elastomer modified polypropylene which has opened a major market for plastic materials in the field of the automotive bumpers. For this highly innovative utilization a severe set of properties has to be ensured by the material and in particular ... 

Toyota CRDL and Toyota Motor Company have developed a Tjumper to bumper recycling system for painted thermoplastics (elastomer modified polypropylene and Toyota Super Olefin Polymer (TSOP), hereeifter referred to as TP) bumpers. 

Elastomer modified polypropylene grades for injection molding. DSM 1991. 0-08-04-01. 

Rubber modified polypropylene polypropylene/ethylene propylene rubber blends ethylene propylene rubber, polypropylene blends elastomer modified thermoplastic elastomer modified polypropylene impact modified polypropylene olefin thermoplastic elastomer thermoplastic polyolefc rubber. 

Product range 12 grades. Keltan elastomer modified polypropylene Keltan iniection mouldina arades 0300. 0505. 0552/2. 0603. 0603A. Keltan iniection mouldina extrusion arades 2609. 2617. 2632. i (EMPP) and Kelburon (R-EMPP). 2605, 2607. 

In the early stages of development of polypropylene rubbers, particularly butyl rubber, were used to reduce the brittleness of polypropylene. Their use declined for some years with the development of the polypropylene copolymers but interest was greatly renewed in the 1970s. This interest has been centred largely around the ethylene-propylene rubbers which are reasonably compatible in all proportions with polypropylene. At first the main interest was with blends in which the rubber content exceeded 50% of the blend and such materials have been designated as thermoplastic polyolefin elastomers (discussed in Section 11.9.1). There is also increasing interest in compounds with less than 50% rubber, often referred to as elastomer-modified thermoplastics. It is of interest to note... 

The structure of crystalline polymers may be significantly modified by the introduction of fillers. All aspects of the structure change on filling, crystallite and spherulite size, as well as crystallinity, are altered as an effect of nucleation [9]. A typical example is the extremely strong nucleation effect of talc in polypropylene [10,11], which is demonstrated also in Fig. 2. Nucleating effect is characterized by the peak temperature of crystallization, which increases significantly on the addition of the filler. Elastomer modified PP blends are shown as a comparison crystallization temperature decreases in this case. Talc also nucleates polyamides. Increasing crystallization temperature leads to an increase in lamella thickness and crystallinity, while the size of the spherulites decreases on... 

Impact-modified polypropylenes are produced by combining the homopolymer with an ethylene-propylene copolymer rubber. Ziegler-Natta processes yield such products in cascaded reactors. The first reactor in the sequence produces a rigid polymer with a high propylene content and feeds the second reactor, where the ethylene-propylene elastomer is polymerized in intimate mixture with the first material. 

Polypropylene homopolymer, polypropylene copolymer, and a polypropylene elastomer blend (TPO) were melt compounded with 2.0,4.0, and 6.0 wt% additive. Additional tests with additive levels of 0.5,1.0 wt, and 1.5 wt% were made with Struktol TR-016. HiMod-360 mica was used at 30 wt% levels in all formulations, and there was a constant 0.2 wt% level of a stabilizer package in each compound. The maleic anhydride-modified polypropylene most effective in increasing performance properties was Unite MP-1000, but many other similar products made by a variety of companies performed nearly as well. To select the very best product, one must consider the relative costs of such additives and required use levels. 

It should be noted that there are literally hundreds of different polypropylene resins available for use in producing mica-reinforced composites. There are also many different types and suppliers of anhydride-modified polypropylene that can be used successfully, and there are many types of elastomer suitable for use in TPO formulations. The above information is provided to show the importance of the use of additives when designing mica-reinforced TPO composites. Well-planned experimental designs are needed to determine optimum formulations. 

Moplen is Himont s trade name for polypropylene resins. SP series includes elastomer-modified, reinforced and non-reinforced grades. 

When the conductive filler locahzes in a minor phase of a blend, that phase must be at least partially continuous for the composite to be globally conductive. Morphology is often adjusted to keep a conductive minor phase volume to a minimum, while maximizing continuity in an attempt to minimize the additional cost incurred for the conductive filler. For example, in a rubber-modified polypropylene, the carbon resides in the minor rubber phase. Figure 30 shows that the minor phase rheology of a conductive TPO. For this, the conductive carbon resides fully in the elastomer phase, which is the dark region. The minor elastomer phase morphology has been adjusted to be somewhat lamellar so that the conductive domains can be continuous within the composite at low-volume fractions. 

If the rubber content of a PP blend is less than 50%, then the material may be referred to as rubber reinforced polypropylene (RRPP) or, as rubber modified polypropylene ( PP) or, as an elastomer modified thermoplastic MT) or, as an olefin thermoplastic elastomer (OTE) or, as impact modified polypropylene (IMPP). The material may also be known as a thermoplastic elastomer (TFE) or, as a thermoplastic rubber (TPR). The rubber/elastomer in such a mbcture is not crosslinked, or cured, or vulcanized). The term rubber reinforced PP (RMPP) will be used for those systems in which the rubber is present in relatively low concentations (<30%) and is not cross-linked/cured. 

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

Modified Bitumen Membranes. These membranes were developed in Europe during the late 1950s and have been used in the United States since the late 1970s. There are two basic types of modified asphalts and two types of reinforcement used in the membranes. The two polymeric modifiers used are atactic polypropylene (APP) and styrene—butadiene—styrene (SBS). APP is a thermoplastic polymer, whereas SBS is an elastomer (see Elastomers, thermoplastic elastomers). These modified asphalts have very different physical properties that affect the reinforcements used. 

Blends of isobutylene polymers with thermoplastic resins are used for toughening these compounds. High density polyethylene and isotactic polypropylene are often modified with 5 to 30 wt % polyisobutylene. At higher elastomer concentration the blends of butyl-type polymers with polyolefins become more mbbery in nature, and these compositions are used as thermoplastic elastomers (98). In some cases, a halobutyl phase is cross-linked as it is dispersed in the polyolefin to produce a highly elastic compound that is processible in thermoplastic mol ding equipment (99) (see Elastomers, synthetic-thermoplastic). ... 

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