Polypropylene functions

The introduction of reactive components during blend formation further increases the complexity of the process and affects results. Polypropylene functional-... 

Single clay layers or 100% dispersion of the clay in polymer matrices is also the ideal situation in which to obtain nanocomposite materials with enhanced mechanical properties. This was achieved by researchers at the Pennsylvania State University ° with a semifluorinated organic surfactant to modify the montmorillonite, which is subsequently compounded with polypropylene (functionalized with, e.g., maleic anhydride). In The Netherlands the clay is intercalated with polyethyl-... 

Hyde, J. Licence, P. Carter, D. Poliakoff, M. (2001) Continuous Catalytic Reactions in Supercritical Fluids. Appl. Catal., A. Vol.222, No.1-2, pp.119-131 Jin, S. Kang, C Yoon, K Bang, D. Park, Y. (2009) Elect of compatibilizer on morphology, thermal, and rheological properties of polypropylene/functionalized multi-walled carbon nanotubes composite. /. Ayyl. Polym. Set. Vol.lll, No.2, pp.1028-1033 Joen, H Jung, H Lee, S. Hudson, S. (1998) Morphology of polymer/Silicate Nanocomposites Hieh Density Polyethylene and a Nitrile Copolymer. Polym. Bull. Vol.41, No.l, pp.107-111... 

Giildogan, Y., Rzayev, Z. M. O., and Pi kin, E. 2004. Polypropylene functionalization in solution and in melt by reactive extrusion, in Abstract 11th International Conference on Polymers and Organic Chemistry, Praque, Czech., p. P42. 

Ruggeri, G., Aglietto, M., Petragnani, A., and Ciardelli, F. 1983. Some aspects of polypropylene functionalization by free radical reactions. European Polymer Journal 19 863-866. 

Shortly after controlled degradation technology was developed, pioneer workers explored polypropylene functionalization reactions in extruders (1). The early work involved grafting of maleic anhydride onto polypropylene to improve adhesion properties. Later work involved grafting other monomers, and even polymers, onto polypropylene in twin-screw extruders. 

The development of extruder-based polypropylene functionalization technology followed that of controlled degradation technology. The early work related to grafting of monomers, such as acrylic acid (AA) and maleic anhydride (MA), onto polyolefin backbones (1). Initial studies were done with single-screw extruders, whereas more recent work has concentrated on using twin-screw extruders because of their superior mixing performance. A survey of the early work is presented in Brown (9). 

Single-Stream Polypropylene Functionalization-Glass Fiber Incorporation... 

Shiono, T. Kurosawa, H. Ishida, O. Soga, K. Synthesis of polypropylenes functionalized with secondary amino groups at the chain ends. Macromolecules 1993, 26, 2085-2089. 

Klingert B. Influence of stabilizers on light and thermal stability of filled polypropylene. Functional fillers and additives for thermoplastics and rubber conference. Berlin September 1994. p. 26-28. 

The spring ensures a soHd closing action and is usually wound from stainless steel wire. The dip tube conducts the product from the container to the valve. It is usually extmded from polyethylene or polypropylene and has an inside diameter of over 2.54 mm, although it can be provided in capillary sizes having diameters down to 0.25 mm. These small tubes are used to reduce flow rate and may function in place of the Hquid metering orifice in the valve housing. 

Fabric Composition. The method of fabric manufacture dictates many of the characteristics of the sheet, but intrinsic properties are firmly estabhshed by the base polymer selected. Properties such as fiber density, temperature resistance, chemical and light stabiUty, ease of coloration, surface energies, and others are a function of the base polymer. Thus, because nylon absorbs more moisture than polypropylene, spunbonded fabrics made from nylon are more water absorbent than fabrics of polypropylene. 

Polypropylene molecules repeatedly fold upon themselves to form lamellae, the sizes of which ate a function of the crystallisa tion conditions. Higher degrees of order are obtained upon formation of crystalline aggregates, or spheruHtes. The presence of a central crystallisation nucleus from which the lamellae radiate is clearly evident in these stmctures. Observations using cross-polarized light illustrates the characteristic Maltese cross model (Fig. 2b). The optical and mechanical properties ate a function of the size and number of spheruHtes and can be modified by nucleating agents. Crystallinity can also be inferred from thermal analysis (28) and density measurements (29). 

Carbon Cha.in Backbone Polymers. These polymers may be represented by (4) and considered derivatives of polyethylene, where n is the degree of polymeriza tion and R is (an alkyl group or) a functional group hydrogen (polyethylene), methyl (polypropylene), carboxyl (poly(acryhc acid)), chlorine (poly(vinyl chloride)), phenyl (polystyrene) hydroxyl (poly(vinyl alcohol)), ester (poly(vinyl acetate)), nitrile (polyacrylonitrile), vinyl (polybutadiene), etc. The functional groups and the molecular weight of the polymers, control thek properties which vary in hydrophobicity, solubiUty characteristics, glass-transition temperature, and crystallinity. 

The chelated organic titanates also function as adhesion promoters of the ink binder to printed substrates such as plastic films, paper, and aluminum foil (504). The acetylacetone complexes of titanium are the preferred products for promoting adhesion of printing inks to polypropylene films. 

---