Reinforced polypropylene resin

Table 3.26 Properties of increased glass content recycled reinforced polypropylene resin...

Given that small working mass is a more economical means of reactive extrusion, the distinction between different types of extrusion equipment branches off into a whole host of processing attributes. Because of increasing trends in the late 1990s to replace single extruders by twin-screw extruders, our attention is now directed at twin-screw methodology to modify and reinforce polypropylene resins into a wide spectrum of composite materials. 

The final combination of ingredients promotes an adhesive bond between the polymer matrix and load-bearing glass-fiber reinforcement. Consequently, the physicochemical characteristics of the microstructure based on the interphase design determine the ultimate mechanical and other properties of filled or glass-fiber reinforced polypropylene resins. 

The 30% glass-reinforced polypropylene resin has a unique decrease of approximately 25% in work-to-break with increasing test speed above the 0.05 in./min range (Fig. 3-4). An extremely large work-to-break value is demonstrated by the 40% glass-reinforced polyurethane resin (55D Shore Durometer Hardness Base Resin) at the 0.05 in./min straining rate (Fig. 3-9). 

In a recent study, the interphases for different fiber/polymer matrix systems were investigated. By using phase imaging the differences in local mechanical property variation in the interphase of glass fiber reinforced epoxy resin (EP) and glass fiber reinforced polypropylene matrix (PP) composites could be unraveled. As shown in Fig. 3.68, the glass fiber, the interphase and the PP matrix can be differentiated based on their surface mechanical properties as assessed qualitatively by TM phase imaging. 

GFN1—10% giass fiber reinforced, polypropylene ether, and PS blend resin. 

Figure 3.89 Stress vs. strain at various temperatures for SABIC Innovative Plastics Noryl GTX GTX830—30% glass fiber reinforced, polypropylene ether, PS, and polyamide blend resin.

Generally, the TPOs are produced by extruder compounding processes in which the polypropylene resin is blended with an ethylene copolymer mbber (EPR or other polyolefin elastomers or POEs), along with a desired level of reinforcing fillers. The components are blended together at 210-270 °C imder high shear using a twin-screw extmder or a continuous mixer. 

Bis(jS-hydroxyethyl-y-aminopropyltriethoxy silane n. A silane coupling agent used in reinforced epoxy resins, also in many reinforced thermoplastics such as PVC, polycarbonates, nylon, polypropylene, and polysulfones. 

Polypropylene is a very versatile polymer. It has many properties that make it the polymer of choice for various applications (e.g., excellent chemical resistance, good mechanical properties and low cost). There are many ways in which the mechanical properties of polypropylene can be modified to suit a wide variety of end-use applications. Various fillers and reinforcements, such as glass fiber, mica, talc, and calcium carbonate, are typical ingredients that are added to polypropylene resin to attain cost-effective composite mechanical properties. Fibrous materials tend to increase both mechanical and thermal properties, such as tensile strength, flexural strength, flexural modulus, heat deflection temperature, creep resistance, and sometimes impact strength. Fillers, such as talc and calcium carbonate, are often used as extenders to produce a less-costly material. However, some improvement in stiffness and impact can be obtained with these materials. 

Similar types of results are reported with the use of maleated polypropylenes. In an article by Borden et al. (34), mechanical property improvements of 9-29% are shown with the addition of 10% maleated polypropylene. Another article by Hyche et al. (32) indicated that the use of medium-molecular-weight, highly functionalized PPgMAH works better than high-molecular-weight, low functionalized material in mica filled polypropylene. Chapter 14 provides a detailed discussion of mica reinforcement of polypropylene resins. 

X Leguet, M Ericson, D Chundury, G Baumer. Filled and Reinforced Polypropylene Compounds as Alternatives to Engineering Resins. ANTEC, SPE, Toronto,... 

Traditionally, material design requirements that suit such demanding end-use applications have been limited within the domain of engineering plastics based on polyamide 6 or 66, polyester alloys, and polyacetal type resins. However, as described in Chapter 1, glass fiber-reinforced polypropylene (GFRP) composites continue to gain a market share in automotive molded parts. 

Mica is combined with polyolefin resins to make composites that compare favorably to widely used engineering resins. These reinforced compounds are now replacing acrylonitrile butadiene styrene (ABS), glass fiber-reinforced polypropylene, various grades of nylon and polyester resins, and steel in many applications. 

A study of the effects of 11 surface-treating agents and three modified polypropylene resins on the strength properties of mica-reinforced polypropylene was presented in a paper at the 1990 annual SPI conference (28). HAR-160 mica, the mica used in the previous section on annealing, was also used in this study. The polypropylene used in the study was Profax 6523 pm, which has a nominal melt index of 4. Surface treatments and treatment levels are listed in Table 14.29. 

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. 

Gapex, Engineered polypropylene resins, Ferro Corp., Filled Reinforced Plastics Div. 

The stiffness of common plastics materials is very low compared with steel (flexural modulus of most common thermoplastics 2 GN m 2, modulus of steel 200 GM m"2). Glass reinforcement greatly increases the stiffness of plastics, both thermosetting and thermoplastic - see Philips glass-coupled polypropylene washing machine tank. Chapter 9. For example, the flexural modulus of cast unsaturated polyester resin 3.5 GN m 2, flexural modulus of GRP (glass reinforced polyester resin) SGM m"2. 

General discussions of the effect of reinforcing agents on the thermal properties of polymers include glass fiber-reinforced polyethylene terephthalate [28], multiwalled carbon nanotube-reinforced liquid crystalline polymer [29], polysesquioxane [30, 31], polynrethane [31], epoxy resins [32], polyethylene [33], montmorillonite clay-reinforced polypropylene [34], polyethylene [35], polylactic acid [36, 37], calcium carbonate-filled low-density polyethylene [38], and barium sulfate-filled polyethylene [39]. 

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

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