Intentional degradation by pro-oxidant agents, many of which are metal-based, can result in uncertainty as to the time of biodegradation. Polyacetal (POM) is a thermoplastic polymer commercially classified as an engineering polymer and contains carbon, hydrogen and oxygen. The depolymerization of POM during processing can enhance thermal decomposition. The aim of this study was to investigate t...

OBJECTIVE A retrospective cohort study of 640 male polypropylene production workers in Germany was performed to evaluate the reported association between colorectal cancer and polypropylene. METHOD The follow up period was 1956 to 1990. Expected numbers of cancers were derived from incidence rates adjusted for age and calendar year from the Saarland cancer registry. RESULTS Three colorectal...

The effects of surface treatment of flax fibers featuring vinyltrimethoxy silane (VTMO) and maleic anhydride-polypropylene (MAPP) on the mechanical properties of flax/PP composites were investigated. α-polypropylene (α-PP) and β-polypropylene (β-PP) were used as matrices for measuring the mechanical properties of the flax fiber/polypropylene (flax/PP) composites. Flax/PP composites composed of ...

This study presents an application of artificial neural networks (ANN) for the prediction of repeated creep test results for polypropylene (PP) modified asphalt mixtures. Polypropylene fibers are used to modify the bituminous binder in order to improve the physical and mechanical properties of the resulting asphaltic mixture. Marshall specimens, fabricated with M-03 type polypropylene fibers at...

AIMS To evaluate in vivo fibroplasia and biological stability of porous polymers intended for use in the Seoul-type keratoprosthesis (S-KPro). METHODS Four porous polymers (polypropylene, two kinds of polyethylene terephthalate (PE70 and PE50), and polyurethane) were investigated. Discs of polymers were inserted into the corneal stroma of rabbits for a 2 and 5 month period. Corneal oedema and...

PURPOSE To compare the inflammatory reaction and the growing resistance of the abdominal wall with the use of poliglecaprone meshes and polypropylene meshes associated with poliglecaprone in the correction of abdominal defects. METHODS Seventy-seven Wistar rats were divided into three groups: CG (non-operated animals: EG (polypropylene mesh) and UG (polypropylene and poliglecaprone mesh). A m...

Objective. This study was designed to observe the histocompatibility and long-term results of wigs after xenogeneic hair transplantation and to explore the possibility of industrial products in clinical application. Methods. The human hair and melted medical polypropylene were preceded into the follicular unit-like wigs according to the natural follicular unit by extrusion molding. 12 New Zeala...

Polymer nanocomposites are new classes of composite materials derived from nanoparticles with at least one dimension in the nanometric range. Polypropylene nanocomposites have attracted a considerable interest due to its most widely used and fastest growing classes of thermoplastic polymer with low cost and low density. However, a problem associated with polypropylene is its dyeability. There h...

Polypropylene (PP) is typically solid phase thermoformed at temperatures close to its crystalline melting point, usually in the 150° to 160° Celsius range. In such conditions the mechanical properties of the material rapidly decline with temperature and these large changes in properties make Polypropylene one of the more difficult materials to process by thermoforming. This paper presents the f...

Polypropylene/Multiwall carbon nanotubes/Montmorillonite (PP/MWNTs/MMT) hybrid nanocomposites were prepared by using twin-screw extruder incorporating the polypropylene grafted maleic anhydride (PP-g-mA) as compotibilizer is used for better dispersion of nanoclay in the polymer matrix. The effect of MWNTs and MMT on the polypropylene matrix was investigated in terms of mechanical properties of ...