Polypropylene mica filled

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. 

AM Adur, RC Constable, J Humeiuk. Performance Enhancement in Mica Filled Polypropylene Obtained by Addition of Chemically Modified Polyolefins. ANTEC, 1998, pp. 1474-1477. 

A comparison of the properties of surface-treated phlogopite mica with talc, calcium carbonate, glass, and the unfilled resin is given in a technical bulletin produced by Marietta Resources International, Ltd. (10). Table 14.7 shows that 40 wt% mica-filled polypropylene (Profax 6523) had a higher flexural modulus than 30 wt% glass fiber-filled polypropylene (1.04 X 10 psi versus 0.93 X 10 psi). The compound filled with 40 wt% surface-modified mica also had higher Izod impact than the 40 wt% talc-filled compound (0.65 versus 0.45 ft-lb/in). 

FJ Meyer. Metal replacement with mica-filled polypropylene. Body Eng J 57-62, Fall 1979. 

KA Borden, RC Weil, CR Manganaro. The effect of polymeric coupling agent on mica-filled polypropylene optimization of properties through statistical experimental design. Proceedings of the 51st Annual Technical Conference, SPE, New Orleans, LA, 1993. 

Dover Chemical quotes data from Ford Motor Co. that its Hordaresin NP 70 and Chlorez 700 grades can also function as coupling agents in mica-filled polypropylene. The compounds show sufficiently low cost and high modulus to make them economic replacements for certain applications where steel is normally used. Use of lower-cost mica in place of glass fibre can also offer potentially large cost savings. 

Mica-filled polypropylene is now the largest volume market for mica. Some typical applications and benefits are ... 

Chemical coupling agents for glass and mica filled polypropylene systems. 

Compounded mica filled polypropylenes are available from a number of manufacturers, with however a large offer from India (where are the largest deposits of mica). Grades up to 40% are marketed and Table 6.11 is a compilation of typical average properties, based on manufacturers data sheets. 

Low Cost Fan Shrouds on Ford F-150, Expedition, Navigator, Ranger are made of PP-5140-F1, a 40% talc polypropylene replacing glass/mica-filled polyamide fan shrouds. 

Polypropylene (G/F)/nylon 6,6 Polyurethane open/closed cell foam Polypropylene (mica filled/glass filled/mineral filled) Aluminum tube AA4343/AA3003 base Aluminum tube AA4343/AA3003 base Nylon 6,6/nylon 6/polypropylene Nylon 6,6/nylon 6 Polypropylene (GF)... 

Polypropylene composites have many advantages over metal such as corrosion resistance, low weight, easily molded complicated shapes, and low cost. A 1979 article (1), compared the cost of polypropylene composites versus steel sheet at equal stiffness (Table 14.1). Mica-filled (40 wt%) polypropylene was the only composite with a relative cost less than that of steel (0.98) for a part with stiffness equal to steel. The relative thickness of the composite was 2.88 and the relative weight was 0.45. Cost calculations were based on mica at 0.18/ lb and polypropylene at 0.31/lb. The relative cost of a 40% glass-filled polypropylene composite was 2.48 and its relative weight was 0.49. The relative cost of a 40 wt% filled talc/polypropylene composite was 1.32 and the relative weight was 0.61. 

The relatively large amounts of iron in phlogopite mica (Table 14.2) are likely the cause of the poorer heat aging characteristics of phlogopite-filled polypropylene relative to that of muscovite mica. 

A paper presented at the 1990 SPE ANTEC (5) discussed techniques for compounding highly filled polymers with corotating twin-screw extruders. The fusion time as measured in a torque rheometer of 40 wt% filled polypropylene with melt flow index (MFI) of 15 was 2.4 min for glass fibers, 8 min for mica, and 13.5 min for talc. For a 30 wt% loading of mica, fusion time was reduced to about 5 min. 

Extrusion rates are also increased by use of surface treated mica (6). The extrusion rate increased 20% for a 50 wt% filled polypropylene homopolymer compound using surface-modified mica. 

Contrary to what one might believe, the melt flow of mica-reinforced polypropylene is not decreased substantially when one increases the mica loading level. In a recent paper (8), the melt flow of 20, 30, and 40 wt% filled polypropylene homopolymer decreased only slightly with higher levels of mica. The melt flow decreased from 2.9 g/10 min for 20 wt% mica to 2.6 g/10 min for 30 wt% and 1.8 g/10 min for 40 wt% mica. 

Mica particle size has significant effects on most composite properties. Table 14.23 shows these effects for a 30 wt% filled polypropylene copolymer composite. It is not possible to get good trends from this table based on particle size only. These products were prepared by different methods including wet grinding, dry grinding, and screening of spiral mica. These production processes provide different degrees of and different aspect ratios for particles of similar diameter. 

Effects of mica particle size on 30 wt% filled polypropylene copoiymer, Profax 8623. Source. Ref. 41. 

Faulkner, D.L. and Schmidt, L.R. (1977) Glass bead-filled polypropylene Part I Rheological and mechanical properties, Polym. Engg Sci., 17,657-64. Boira, M.S. and Chaffey, C.E. (1977) Effects of coupling agents on the mechanical and rheological properties of mica-reiitforced polypropylene, Polym. Engg Sci., 17,715-18. 

Mica provides similar benefits in a wide range of thermoplastic and thermoset composites including polyolefins, polyamides and styrenics. It is also reported that surface coated mica further increases tensile strength, flexural strength and modulus, and heat deflection temperature. The automobile industry is the main user of mica-filled composites, either with polypropylene or nylon as polymer matrix. Up to 40% mica loadings are used, sometimes in association with calcium carbonate, to produce various injection... 

Effect of mica volume fraction on the flexural and elasticity moduli of commercial filled polypropylene compounds clear squares are average moduli data shaded diamonds are data from one selected supplier the dotted curve was calculated with the Guth and Gold equation and Epoiyn, = 1.152 GPa and 1.191 GPa for the flexural and elasticity moduli, respectively the solid curve was calculated with the modified Guth and Gold equation and an anlsometry factor/= 3.3. 

Tapes. A great variety of tapes find application in electrical equipment. Some tapes contain filler materials in macroscopic form such as glass fibers, mica flakes, and cloth others have finely divided filler particles or no fillers at all. In the heavily filled materials the polymeric binders are present in small fractions, and the major emphasis may be on their adhesive capabilities rather than on their properties as dielectric materials. Most of the polymers used in tapes have already been mentioned in connection with other insulation applications, for example, polyesters, aromatic polyamides, polyimides, and polypropylene. Other polymers frequently used for electrical tapes are vinyls, including poly(vinyl fluoride) these are particularly well suited as conformable tapes. Polytetrafluoroethylene (Teflon TFE) has also been fabricated into tape constructions, frequently in combination with adhesives to provide a bondable material. 

Mica is not in nse—so far—as a mineral filler for WPCs. However, it was rather extensively stndied in model WPC systems. Generally, it behaves similarly with calcinm carbonate in some systems—decreases flexnral modnlns of 60-mesh pine wood flonr (16.7% and 25% w/w)-filled oriented polypropylene from 10 to 20 to 30% loading level of mica (overall from 390,000-420,000 psi with no mica to 320,000 psi with 20 and 30% w/w of mica), and also decreases flex strength in the same system from 6500 psi (control) to 4000-5000 psi. As the anthor of the stndy [9] has noticed, comparisons with other phyllosilicates show mica to have the least benehts. 

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