Toughened polypropylene

Some of the most difficult heterophase systems to characterize are those based on hydrocarbon polymers such as mbber-toughened polypropylene or other blends of mbbers and polyolefins. Eecause of its selectivity, RuO staining has been found to be usehil in these cases (221,222,230). Also, OsO staining of the amorphous blend components has been reported after sorption of double-bond-containing molecules such as 1,7-octadiene (231) or styrene (232). In these cases, the solvent is preferentially sorbed into the amorphous phase, and the reaction with OsO renders contrast between the phases. 

An increasing variety of automotive parts is being made by thermoforming processes. Many of these products are made from rubber-toughened polypropylene, which are relatively stiff and can withstand a high level of physical abuse over a ivide range of temperatures. When such parts are used in high visibility areas, such as wheel arches, air dams, truck fenders, and... 

The preferred average particle size 1n HIPS was believed to be 0.8 ijm (J.). However, our current data indicate that a number average particle diameter of 1.05 urn and 0.5 -urn appear to be a preferred size for HIPS and rubber-toughened polypropylene (PP), respectively. The morphology of the rubbery phase in a toughened PP appears to be less complex, as evidenced in Figure 2 where the dark, also osmium-stained, phase is the styrene-butadiene rubber (SBR) particles. No PP occlusions were found in this material since it is a physical blend of SBR and PP. 

Figure 2. Rubbery phase morphology of a toughened polypropylene.

Toughened polypropylene may be prepared by block copolymerization in which ethylene monomer is added during the final stages of the polymerization of propylene (4). Thus, some polypropylene chains would contain an end block of rubbery ethylene-propylene copolymer. Alternatively, a blend of an elastomeric copolymer of ethylene and propylene (EPR or EPDM) with isotactic polypropylene (PP) can produce an impact-resistant polymer (5). 

Toughened Polypropylene-Polyamide 6 Blends Prepared by Reactive Blending... 

DMA measurements are intensively used to investigate the amorphous phase transitions of polymers. The results of DMA studies were published by authors like Schmieder and Wolf [2], Nielsen and Buchdahl [3] and Heijboer [4]. Neat polymers, but also polymer blends and polymer systems blended with fillers, plasticisers or impact improvers were investigated by DMA. An example of such an application is given for toughened polypropylene in 4.1.2. 

There have been extensive applications of isotactic polypropylene (iPP)/EPM blends. These were used to produce rubber toughened polypropylene blends and subsequently polyolefin thermoplastic elastomers (88,89). Most commercial EPMs contain more than 50 mol% of ethylene, and these are elastomers. The solubility parameter of EPM should be intermediate to those of polyethylene and polypropylene dependent on ethylene content. Thus, it is often used to compatibilize PE/PP blends (90,91). 

Y. Li, G.-X. Wei, and H.-J. Sue, Morphology and toughening mechanisms in clay-modified styrene-tutadiene-styrene rubber-toughened polypropylene, J. Mater. Set, 37, 2447-2459 (2002). 

G. Liu, G. Qiu, Study on the mechanical and morphological properties of toughened polypropylene blends for automobile bumpers. Polym. Bull. 70(3), 849-857 (2013)... 

You are designing a plastic chair with the aid of a finite-element program, and have chosen a toughened polypropylene for the application. Creep data for the material at 23°C are available in graphical form for space reasons, they are given here by the equation ... 

The toughened polypropylene of Example 8.2 is to be used in constructing a cylindrical water tank. The tank will have a diameter of 3 m and a height of 2.5 m. It will be full for 4 months, and then left empty for 8 months before being refilled. Calculate the wall thickness required to ensure that the residual strain m the wall does not exceed 0.05% at the end of the first year. Neglect constraints imposed by the base of the tank. 

The creep of a rubber-toughened polypropylene at TXfC can be fitted to the equation... 

Lim, J. W., Hassan, A., Rahmat, A. R., and Wahit, M. U. 2006. Rubber-toughened polypropylene nanocomposite Effect of polyethylene octene copolymer on mechanical properties and phase morphology. Journal of Applied Polymer Science 99 3441-3450. 

The first step in selecting a material for a particular application is to define the properties that are essential to the performance of the component. In some cases, the requirements limit the choice to one or two materials. For example, expansion joints in some chemical installations require a combination of flexibility with resistance to extremely corrosive environments the bellows shown in Fig. 8.1 are made from PTFE, despite its high price and difficulties in processing, because no materials other than fluorocarbon polymers meet the requirements. On the other hand, several less expensive polymers have sufficient resistance to dilute sulphuric acid to make a satisfactory battery case toughened polypropylene is chosen for its combination of chemical resistance, stiffness, toughness, processability, and moderate price. 

A chair seat to be injection moulded in toughened polypropylene will consist... 

It must be pointed out that although both polyethylene and polypropylene are crystalline polymers, the random polymer at midrange compositions is totally amorphous. These materials, with a glass transition of -50°C, make especially good elastomers for toughening polypropylene plastics (134-136). 

Chen, E. E., Wong, B., and Baker, W. E. (1996). Melt-grafting of glycidyl methacrylate onto polypropylene and reactive compatibilization of rubber toughened polypropylene. Polymer Engineering and Science 36(12), 1594-1607. 

Xiaoguang Zhu, Xiaohua, Deng Xuan Hong et al. Toughening polypropylene composites filled fracture toughness and the toughening mechanism. Acta Polymerica Sinica, 39(2) 195-201, 1996. 

The surface content and the distribution of (ethylene-propylene) copolymer (EP) in toughened polypropylene (PP) resins (PP/EP) have important impact on a lot of properties such as gloss, paint adhesion, hardness,. .. These surface properties are more and more important in the multiple applications of these resins, for instance for paint adhesion in the automotive industry. It has already been shown that the introduction of EP in PP provides better paint adhesion but its role remains speculative (1-4), A major drawback to the understanding of the EP influence on PP/EP surface properties is the lack of knowledge concerning the blends surface morphology (EP content, EP lateral distribution,. ..). This is essentially due to the similar chemical composition of both polymers that prevents surface analysis by classical chemical surface spectroscopies. 

Martinatti, F. and Ricco, T. (1994) High rate testing of toughened polypropylene. Polym. Testing, 13,405. 

Quazi R T, Bhattacharya S N and Kosior E (1999) The effect of dispersed paint particles on the mechanical properties of rubber toughened polypropylene composites, J Mater Sci 34 607-614. 

Dasari A, Zhang Q-X, Yu Z-Z and Mai Y-W (2008) Significance of submicron to nano-sized voids in toughening polypropylene, in preparation. 

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. 

Zhang L, Wei T, Chen H, Lai W, Bu J. Mechanical and thermal properties of muscovite and density polyethylene-reinforced and toughened polypropylene composites. Journal of Wuhan University of Technology-Mater Sci Ed 2009 24(4) 581-7. 

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