Polypropylene whiskers

Chauve et al. [253] utilized the same technique to examine the reinforcing effects of cellulose whiskers in EVA copolymer nanocomposites. It was shown that larger energy is needed to separate polar EVA copolymers from cellulose than for the nonpolar ethylene homopolymer. The elastomeric properties in the presence of spherical nanoparticles were studied by Sen et al. [254] utilizing Monte Carlo simulations on polypropylene matrix. They found that the presence of the nanofillers, due to their effect on chain conformation, significantly affected the elastomeric properties of nanocomposites. 

Current research indicates that there is a growing interest in natural fibers. Natural fibers Ifom jute were tested in thermosetting and thermoplastic resins. Lignin fillers were used in phenol-formaldehyde, SBR, SBS, and S1S ° and with good results. The opportunities for applications of natural fibers in industrial products have been the subject of recent reviews. Cellulose whiskers with a high reinforcing value were obtained from wheat straw. " Wood fibers were found applicable to such diverse materials as polypropylene... 

When aluminum borate whiskers were incorporated in SAN/PA-6 blends, the whisker, due to acid/based interaction had a better affinity to PA-6 than to SAN and for this reason they ended up in residence in the polyamide phase. A similar principle was used to obtain a conductive blend by compounding PA, PP and carbon black. Carbon black has a better affinity to polyamide and thus it prefers to reside in the polyamide phase or in the interphase formed between two immiscible polymers. Even when carbon black is added initially to polypropylene, it still transfers to the polyamide phase. This migration and preferential location of carbon black is not only an interesting scientific principle but it also has important practical implications. For the purpose of conductivity, a certain threshold concentration of carbon black is required to enable percolation and this threshold concentration is substantially lower if the carbon black settles in only one phase. This phase be-... 

Types of reinforcements include fibers of glass, carbon, graphite, boron, nylon, polyethylene, polypropylene, cotton, sisal, asbestos, metals, whiskers, etc. Other types and forms of reinforcements include whiskers, bamboo fibers, burlap fibers, carbon blacks, platelet forms (includes mica, glass, and aluminum), and hemp fibers (Chapter 2). 

Ljungberg, N., Cavaille, J. Y., and Heux, L. (2006). Nanocomposites of isotactic polypropylene reinforced with rod-like cellulose whiskers. Polymer. 47,6285-6292. 

The cellulose based materials that are used as nano-reinforcements are cellulose nanocrystals (i.e. whiskers and nanospheres), nanofibrillated cellulose, regenerated cellulose nanoparticles and electrospun nanofibers. A wide range of polymer matrices have been used to form cellulose nanocomposites. Synthetic polymers such as polypropylene, poly(vinyl chloride) (PVC) [102], waterborne epoxy [103], waterborne polyurethane [104], polyurethane [105], poly-(styrene-co-butyl acrylate) [106], poly(oxyethylene) [107], polysiloxanes [108], polysulfonates [109], cellulose acetate butyrate [110,111], poly(caprolactone) [112], poly(viny 1 alcohol) [113] and poly (vinyl acetate) [114]. Different biopolymers such as starch-based... 

Tjong, S. C. and Meng, Y. Z. 1999. Microstructural and mechanical characteristics of compatibilized polypropylene hybrid composites containing potassium titanate whisker and liquid crystalline copolyester. Polymer 40 7275-7281. 

Fukuzumi H, Saito T, Iwata T et al (2008) Transparent and high gas barrier films of cellulose nanofibers prepared by TEMPO-mediated oxidation. Biomacromolecules 10 162-165 Garcia de Rodriguez NL, Thielemans W, Dulfesne A (2006) Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites. Cellulose 13 261-270 Gousse C, Chanzy H, Excoffier G et al (2002) Stable suspensions of partially silylated cellulose whiskers dispersed in organic solvents. Polymer 43 2645-2651 Gray DG (2008) Transcrystallization of polypropylene at cellulose nanocrystal surfaces. Cellulose 15 297-301... 

Ljungberg N, Cavaille J-Y, Heux L (2006) Nanocomposites of isotactic polypropylene reinforced with rod-like cellulose whiskers. Polymer 47 6285-6292 Lu Y, Weng L, Cao X (2005) Biocomposites of plasticized starch reinforced with cellulose crystallites from cottonseed linter. Macromol Biosci 5 1101-1107 Lu J, Wang T, Drzal LT (2008) Preparation and properties of microfibrillated cellulose polyvinyl alcohol composite materials. Compos Part A 39A 738-746 Magalhaes WLE, Cao X, Lucia LA (2009) Cellulose nanocrystals/cellulose core-in-shell nanocomposite assemblies. Langmuir. doi 10.1021Aa901928j Malainine ME, Mahrouz M, Dufresne A (2005) Thermoplastic nanocomposites based on cellulose microfibrils from Opuntiaficus-indica parenchyma cell. Compos Sci Technol 65 1520-1526 Marchessault RH, Sundararajan PR (1983) Cellulose. In Aspinall GO (ed) The polysaccharides. Academic, New York... 

Li Q, Zhou J, Zhang L (2009) Stmcture and properties of the nanocomposite films of chitosan reinforced with cellulose whiskers. J Polym Sci Part B Polym Phys 47 1069-1077 Lin N, Chen G, Huang J et al (2009) Effects of polymer-grafted natural nanocrystals on the stmcture and mechanical properties of poly(lactic acid) a case of cellulose whisker-graft-polycaprolactone. J Appl Polym Sci 113 3417-3425 Ljungberg N, Bonini C, Bortolussi F et al (2005) New nanocomposite materials reinforced with cellulose whiskers in atactic polypropylene effect of surface and dispersion characteristics. Biomacromolecules 6 2732-2739... 

Isotactic polypropylene composites with tetra-needle-shaped zinc oxide whisker were prepared via melt blending in a twin-screw extruder. The whisker is a p-nucleating agent, which offers higher crystallization temperature, smaller sphemlites, and faster crystalhzation rate than can be obtained in neat iPP. The addition of whisker also increases heat deflection temperature and thermal degradation temperature of iPP composite. ... 

Zhang, 2006), silk fibroin (Noishiki, Nishiyama, Wada, Kuga, Magoshi, 2002) reinforced with cellulose whiskers were reported. Meanwhile, Poly-(styrene-co-butylacrylate) (poly(S-co-BuA)) (Helbert, Cavaille, Dufresne, 1996), poly (vinyl chlo-ride) (PVC) (Chazeau, Cavaille, Canova, Dendievel, Boutherin, 1999), polypropylene (Ljungberg et al., 2005), waterborne polyurethane (Cao, Dong, Li, 2007), were also used as synthetic matrixes. 

Table 3.18 Whiskers Modified with Different Coupling Agents and Applied in Polypropylene...

Nanying Ning, Feng Luo, Ke Wang. Interfacial enhancement by shish-calabash crystal structure in polypropylene/inorganic whisker composites. Polvmer 50(15) 3851-3856, 2009. 

Consider, for example, the preparation of polypropylene composite material filled with calcium sulfate whiskers... 

Figure 4.7 Influence of the filling content of calcium carbonate whiskers on rheological properties of polypropylene matrix (180°C).

Figure 4.9 Influence of different whiskers on the melt flow index of polypropylene.

Yukun Wei, Haojiang Wang, Chun Pang et al. Study on properties of polypropylene modified by whiskers. Synthetic Materials Aging and Application, 35(1) 12-16, 2006. 

Shuhua He, Jianping Zhou, Wanli Fu. Study on electroconductivity of tetragonal zinc oxide whisker (T-ZnOW)/polypropylene composite. Fine and Specialty Chemicals, 15(ll) 29-32, 2007. 

Jian Zhou, Yuqi Wang, Haibin Meng. The performance of the potassium titanate whisker modified polypropylene. Engineering Plastics Application, 33(H) 21-24, 2005. 

Ning Yang, Dayong Gui, Cheng Qian. Study on potassium titanate whisker reinforced polypropylene. China Plastics, 18(1) 71-74, 2004. 

Yuexin Han, Xu Chen, Wanzhong Yin. The research of basic magnesium sulfate whisker filed up polypropylene. Non-Ferrous Mining and Metallurgy, 23(5) 42-45, 2007. 

This modification method has an obvious shortcoming in that excess stearic acid remains on the whisker s surface if not removed. When filling into the polymer, the excess acid molecules will affect the property of materials. We have attempted to fill whiskers modified like this into polypropylene and found that the tensile strength of the composite material is actually lower than that of the pure polypropylene. 

NDZ-lOl and NDZ-102 titanate coupling agents are selected to treat the calcium carbonate whiskers. The tensile properties of polypropylene composites filled by modified calcium carbonate whiskers are shown in Figures 5.13 and 5.14, respectively. 

Research on Polypropylene Filled with Calcium Carbonate Whiskers... 

Figure 6.40 Tensile stress-strain curves of composite materials prepared using an internal mixing-compression molding method, (a) Pure polypropylene, (b) 10% whisker content. 

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