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Blends of polypropylene and polyamide-6,6 have been compatibilized with polypropylene that was carboxylated through a reactive extrusion process with an asymmetric functional peroxide. The compatibilized blends demonstrated a finely dispersed minor phase as shown by SEM. Because of the enhanced dispersion, additions of the carboxylated polypropylene to the blends resulted in a change in the crystallization nucleation mechanism of the PA-6,6 minor phase from heterogeneous to homogeneous in nature. A linear increase in the impact strength and significant enhancement in the tensile properties of the blends was observed with incorporations of the compatibilizer up to 30% of the matrix phase. In addition, the compatibilizing efficiency of the carboxylated polypropylene was compared to that of maleic anhydride functionalized polypropylene. When compared on an equivalent basis (total concentration of carboxylate or anhydride functionality added to the blend), the carboxylated polypropylene demonstrated a slightly better compatibilizing efficiency than that of the anhydride functionalized polypropylene. The higher compatibilizing efficiency of the carboxylated polypropylene was attributed to a higher grafting efficiency of the carboxylation procedure as compared to the anhydride functionalization procedure., INTRODUCTION The development of useful polymer blends has been the subject of intense investigation in recent years, as a result of their growing commercial importance. Since most polymer pairs are [...]

Within the general objective of analyzing and modeling the processability of polypropylene and of its short fiber composites, a statistical analysis of the relationship between processing conditions and final properties has been performed applying modern experimental design concepts. In order to gather the largest amount of information with a manageable quantity of experiments, Taguchi methods were used for the design of injection molding tests and for the analysis of experimental fiber orientation and impact strength results. Two levels of each variable of interest were selected, and the results of the analysis not only show which of the processing variables are predominant but also show that interactions between variables must be taken into account. The approach presented here offers a viable route to the scaling-up of the injection molding process through the reduction of the number of variables in the prediction of the processing behavior of semicrystalline polymers and of their composites., INTRODUCTION The use of polypropylene has increased significantly in last years in different industrial sectors. Other than the typical applications in the form of films and fibers, the utilization of [...]

Research is presented concerning the production of rac-(EBI)ZrCH2CHClR+ intermediates by the insertion of vinyl chloride into rac-(EBI)ZrR+. The rates of insertion of vinyl chloride and propylene are discussed.

The Ford Motor Co., Dearborn, Mich., is using plastic reinforced with rice hulls--a byproduct of rice grain--in an electrical harness in the 2014 F-150. Hulls are sourced from farms in [...]

Single-component, syndiospecific group 3 metallocene catalysts were prepared and led to the discovery of the ligand system of the Cs symmetric zirconocene (2) which appears to be closely related to the Cs symmetric ansa-metallocene catalyst (1). As expected, the bulky (SiMe3) substituents on the lower cyclopentadienyl ligand acted in the same way as the fluorenyl ligand of 1. Surprisingly, 2 in combination with methylaluminoxane in liquid propylene at 0 degree C generated essentially atactic polypropylene.

U.S. Patent 8,075,830 (Dec. 13, 2011), 'Polypropylene Blown Film,' Rodolfo Mier, Mark Miller, and Raleigh McBride (Fina Technology, Houston, Texas, USA). High-clarity, high-gloss polypropylene films can be produced by cast-film, [...]

An industrial chemical found in antifreeze, deicing fluids and liquid detergents could soon join animal feeds, sweeteners and cooking oil as a commercial product made from corn. Randy Cortright and [...]

Applied Market Information Ltd., AMI House, 45-47 Stokes Croft, Bristol BS1 3QP, United Kingdom; Phone: +44 (0) 117 924 9442; Fax +44 (0) 117 989 2128; www.amiplastics.com; e-mail: info@amiplastics.com; 198 [...]

The effects of the injection-molding induced skin-core morphology on the fracture behavior of rubber-toughened polypropylene (RTPP) systems were studied by employing the essential work of fracture (EWF) method. RTPP with 31 wt% ethylene/propylene rubber (EPR) showed no skin-core structure after molding and the EWF approach worked well in this case. In contrast, RTPP with 10 wt% EPR exhibited a pronounced skin-core morphology: EPR depletion and enrichment was observed in the skin and core region, respectively. This morphology caused necking instead of crack growth in deeply double edge-notched (DDENT) specimens under tensile loading along the mold filling direction (MFD). The necking process not only was accompanied by a large scatter but also yielded highly unrealistic specific essential work of fracture ([w.sub.e]) values. This skin-core structure was also the reason for an anistropic EWF response of this system observed by loading the specimens both in longitudinal (L) and transverse (T) directions to the MFD. The failure sequence and its characteristics were studied by light microscopy (LM) and infared thermography (IT). It was concluded that the EWF approach cannot be applied for RTPP with a prominent skin-core structure. Since yielding preceded the limited crack growth prior to necking in the loading direction for the DDEN-T specimen of RTPP with 10 wt% EPR, the yielding-related specific essential work ([w.sub.e,y]) was used for toughness comparison. In case of RTPP with 31 wt% EPR, where yielding was less pronounced prior to the crack growth, the work of fracture until the maximum load was assigned to the yielding-related work of fracture ([w.sub.f,y]) used for computing [w.sub.e,y]. The latter value seems to be closely matched to the plane-strain essential work of fracture value., 1. INTRODUCTION Linear elastic fracture mechanics (LEFM) is often used to characterize the fracture behavior of many polymeric materials. However, this LEFM approach cannot be adopted for toughened polymers that [...]

High-density polyethylene (HDPE) and isotactic polypropylene (PP) were mixed either with a stabilizer or with a stabilizer and a compatibilizer in different mixing ratios. The structure and properties of these blends were analyzed by methods such as torsion pendulum measurements, mechanical short time experiments, electron microscopy, and fracture mechanical toughness tests. The results display a strongly increased impact strength in the HDPE/PP blend with compatibilizer within a specific mixing region. The deformation behavior and the mechanism leading to the increased impact strength of the blends were investigated in tensile tests by acoustic emission analysis and scanning electron microscopy: Increased fibrilation and strong strain was registered in the blend with compatibilizer. The impact strength was modeled, using experimentally measured properties such as energy release rate, matrix and inclusion volumes, the impact strength of each component. The inclusion volume that causes plastic deformation was chosen as an additional parameter. The calculated results are in good agreement with the experimental ones., INTRODUCTION Inexpensive combined thermoplastics are of great interest for technical applications. In particular, blended materials of increased fracture toughness combined with balanced stiffness and strength as well as appropriate processing [...]

An innovative TPV two-phase polymeric system is described. The new TPV is composed of a polypropylene (PP) matrix in which a metallocene-type ethylene/octene copolymer (EO) is dispersed. The EO-copolymers are grafted with vinyl organosilanes, then blended with PP, hydrolyzed and water-crosslinked in a co-rotating, intermeshing twin-screw extruder. The resulting TPV-grades are easy to process into articles showing an attractive range of properties. The advantages are due to blend composition and crosslinking concept. The new TPV's can be-processed without pre-drying. Moldings are characterized by excellent surface quality and absence of odor as a result of the innovative use of the EO elastomer and the modified crosslinking concept. They can easily be colored to any desirable-shade. The reduced cost of ingredients is another advantage of the newly developed thermoplastic elastomers. High ultimate strength ([Σ.sub.R]) and elongation-at-break ([[Epsilon].sub.R]) values as well as a broad spectrum of different Shore A grades open up many new fields of application. The main focus has been on the automotive applications not least because of very low fogging rates., 1. INTRODUCTION With two-digit annual growth rates, thermoplastic elastomers belong to the most interesting recent polymer developments. From the wide family of thermoplastic elastomers new types of polyolefin blends, so-called [...]

Two orienting techniques for stiffening semicrystalline polymers, rolling and die-drawing, are compared with respect to the anisotropy they produce in isotactic polypropylene (PP). Billets of PP were either drawn at 145 ° C through a tapered slotted die in the Leeds large-scale die-drawing machine to reduction ratios R of 2.2, 5.1 and 7.6, or rolled between rolls of 65 mm diameter at 120 ° C to R = 2 to 5. Drawing increased the crystallinity, as estimated from differential scanning calorimetry, density and wide-angle X-ray diffraction (WAXD); it thus disrupts the original PP structure, developing an oriented crystalline structure. WAXD pole figures showed that both die-drawing and rolling oriented the molecular chain axis nearly parallel to the machine direction and the b axis perpendicular to the drawing plane. This approximate uniaxial symmetry was confirmed by ultrasonic measurements of the stiffness matrix. In tensile and falling-dart impact tests, samples failed by delaminating in the drawing plane. Although stresses are applied to the material in quite different ways in die-drawing and in rolling, the geometry of deformation in both is similar, close to plane strain., INTRODUCTION Thermoplastic polymers can be oriented by solid-state forming processes such as hydrostatic extrusion, die-drawing, or rolling to give products with enhanced mechanical properties (1, 2). For two-dimensional forming by [...]

Polypropylene is relatively new in the plastics world, a 1950s product of the academic work of Ziegler and Natta (1) and the Phillips Petroleum industrial labs of Banks and Hogan [...]