Polypropylene resins homopolymer

From the three basic categories of polypropylene, namely, homopolymers, heterophasic copolymers, and random copolymers (with ethylene), there are specialty resins with enhanced capabilities for specific applications. Producers of large blow-molded or thermoformed parts can thus utilize grades with high melt strength to fabricate heat-resistant under-the-hood automotive parts. 

The list of flexible polymeric roll materials suitable for atmospheric plasma processing is expansive. Mainstream resin types include polypropylene (homopolymers, heterophasic copolymers, and random copolymers), polyethylene (low, medium, and high density polyethylene resins), a family of specialty polyolefins which includes polybutene-1, advanced polypropylene resins from in-reactor alloying processes and polypropylene compounds, and fiuoropolymers. By process type, these materials (in mono- or multiple layers) can be generally represented by the following ... 

The original Doufas-McHugh (1,2) two-phase microstmctural/constitutive model for stress-induced crystallization (SIC) is validated for its predictive capability using on-line Raman crystallinity and spinline tension data of two Dow homopolymer polypropylene resins. The material parameters -inputs to the model - are shown to be obtained from lab scale material characterization data oscillatory shear (DMS), rheotens and DSC. The same set of two SIC material parameters are shown to be able to predict the crystallinity profiles along the spinline and tension very well overall. The model captures quantitatively the effect of take-up speed, throughput and MFR on crystallization rate due to SIC. 

Polyacetal Homopolymer Polyelherimide Phenolic Resin Polypropylene Polyvmylidene Difluonde Polyphenylene Oxide Polyphenylene Oxide (Glass Filled) Polyethersulphone I ill ll I i jH... 

Relatively small changes in comonomer content can result in significant changes in physical or chemical properties. Polymer resin manufacturers exploit such relationships to control the properties of their products. The composition of a copolymer controls properties such as stiffness, heat distortion temperature, printability, and solvent resistance. For example, polypropylene homopolymer is brittle at temperatures below approximately 0 °C however, when a few percent ethylene is incorporated into the polymer backbone, the embrittlement temperature of the resulting copolymer is reduced by 20 °C or more. 

Table 6 Comparison of some relevant properties in tbermoforming between -nucleated PP and other classes of polypropylene. 0 means identical to PP-homopolymer without nucleating agent + means good, ++ very good, - bad, - very bad. The data provided for PP block and random copolymers deal with classical resins. Data taken from Wolfschwenger et al. [49]...

Furthermore, monomers from which crystalline homopolymer can be produced, such as high-density polyethylene and polypropylene, can be copolymerized to produce resins with controllably reduced crystallinity and thus greater transparency. The ethylene/propylene copolymers may range from partially crystalline plastics to amorphous elastomers. 

Fortilene . [ Ivay Polymers] Polypropylene homopolymers andcopolyrtras resins for extrusion, sheet, strapping, profiles, inj. molding, caps, closures, thin-wall containers, disposable tableware, films, fibers, filaments. 

Random copolymer resins are produced by mixing the polypropylene monomer at the first stages of polymerization with ethylene or with another comonomer such as butene. With the low level incorporation of comonomer, the resulting resin exhibits somewhat lower stiffness, a lower melting point, and reduced hardness compared with the PP homopolymer. However, it features better transparency, lower blush resistance, and slightly improved impact resistance at 0°C. 

Polypropylene is widely used in both small and large appliances. In small appliances, like electric drip coffee makers, can openers, blenders, and mixers, and in tools, like electric drills, PPs ease of molding, light weight, stiffness, durability, electrical properties, appearance, and cost make it a very attfactive resin choice. Homopolymers and impact copolymers are both used, with an MFR of around 12 g/10 min being the norm. 

Four types of PP resins are available commercially homopolymer, random copolymer, impact copolymer, and reactor TPO. Homopolymer polypropylene (HPP) is the most difficult to impact enhance. All other types of PP are easier to modify because they contain varied amounts of ethylene linkages or ethylene-propylene bipolymers that reduce the stiffness of the base resin and increase its impact resistance. These structures also provide some degree of compatibility with -f ethylene-alpha olefin plastomers. Basic studies conducted using HPP in polypropylene-plastomer blends illustrate principles that apply to other types of PP as well. 

Tables 14.17,14.18, and 14.19 show that addition of mica to polypropylene compounds has a negative effect on Izod impact properties. In each of the three resin systems, Izod impact decreases steadily with increasing amounts of mica. In homopolymer composites (Table 14.17), the largest particle size mica product, L-...

Talc s low cost qualifies it as a extender, for lowering the cost of the compound and extending the resin with minimal sacrifice in physical properties. Its aspect ratio qualifies it as a reinforcing fiUer, for enhancing performance properties of the compound. Polymers filled with platelike talc exhibit higher stiffness, tensile strength, and creep resistance at ambient as well as elevated temperatures. For example, when polypropylene homopolymer is filled with a 40 percent loading of talc, its flexural modulus is tripled from about 200,000 psi to about 600,000 psi. 

ESR spectroscopy has been applied to studies of unsaturation and other structural features in a wide range of homopolymers including polyethylene [101-110], polypropylene [111-121], polybutenes [115], polystyrene [122-124], PVC [125,126], polyvinylidene chloride [127], polymethylmethacrylate [128-137], polyethylene glycol polycarbonates [137-140], polyacrylic acid [136-139, 141, 142], polyphenylenes [143], polyphenylene oxides [143], polybutadiene [144], conjugated dienes [145,146], polyester resins [146], cellophane [143,147] and also to various copolymers including styrene grafted polypropylene [148], ethylene-acroline [149], butadiene-isobutylene [150], vinyl acetate copolymers [151] and vinyl chloride-propylene. 

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