The rheological behaviour of in-situ microfibrillar blends, including a typical semicrystalline/semicrystalline (PETP/HDPE) and a typical amorphous/semicrystalline (polycarbonate(PC)/HDPE) blend was investigated. PETP and PC microfibrils exhibited different effects on the rheological behaviour of microfibrillar blends. The viscosity of the microfibrillar blends increased with increasing PETP and PC concentrations. The length/diameter ratio of the microfibrils, as a result of the hot stretch ratio, had an unexpected opposite effect on the rheological behaviour of the two microfibrillar blends. The stretched PETP/HDPE blend exhibited higher viscosity than the unstretched counterpart, while the stretched PC/HDPE blend exhibited lower viscosity than the unstretched blend. The data obtained should be of use for constructing a technical basis for the recycling and utilisation of PETP, PC and HDPE waste mixtures by manufacturing microfibrillar blends. 37 refs.

The possibility of producing secondary materials by blending recycled PE(RPE) from greenhouses and post-consumer ground tyre rubber(GTR) was studied. The blends were prepared in an industrial twin-screw extruder. RPE pellets and GTR powder were fed to the extruder without any other additive. Temperature, processing speed, mixing procedure and composition were changed in order to study the influence of these parameters on the rheological and mechanical properties. The results indicated that the blends exhibited fairly good properties provided that a relatively low concentration of GTR and suitable thermal conditions were adopted. A filler-like effect due to the partial carbonisation of the GTR phase was also shown, especially at the highest processing temperature. 13 refs.

The extrusion foaming of recycled PE through different foaming agents was studied. Cellular structures were obtained in a single-screw extruder with different grades of PE (LDPE and HDPE), using recycled gypsum and a commercial foaming agent (azodicarbonamide). DSC and TGA were used to characterise the transition temperatures of the PEs used and the dissociation temperature of the foaming agents. The effect of processing conditions on the density of extrudates was studied. The pressure developed during extrusion and the residence time in the die was shown to influence the final density and cellular structure of foamed PE. The results indicated that a higher polymer viscosity corresponded to a lower density of the foamed product. The formation of the gaseous phase should take place at temperatures immediately above the m.p. range of the polymer, in order to allow complete dissociation of the foaming agent in highly viscous molten polymer. 12 refs.

The initial outdoor use of LDPE results in complex chemical, physical and mechanical changes, decreasing material properties of the reclaimed polymer commingled with small amounts of other polymers. An upgrading system was developed which exploited the beneficial chemical changes of the recycled LDPE collected from municipal sources. Analysis of experimental data of melt reprocessing of thermally or photochemically pre-aged LDPE blends with high-impact PS(HIPS) indicated an improvement of impact TS and phase structure after addition of a 1:1 mixture of styrene-butadiene copolymer with EPDM and by restabilisation with N,N'-disubstituted 1,4-phenylene diamine, the latter having a bifunctional character arising from its ability to scavenge both alkyl-peroxy and alkyl radicals. The mechanism of the diamine-mediated compatibilisation process was studied. 12 refs.

The preparation by melt mixing of recyclable composites based on nylon fibre-reinforced high density polyethylene (HDPE), with or without the addition of styrene maleic anhydride grafted HDPE, is described. The mechanical properties, thermal stability and recyclability of the composites were investigated by tensile and flexural tests, SEM of fracture surfaces, TGA and FTIR, and the results are discussed. 16 refs.

According to Chemical Market Resources, Chinese imports of polyolefins are decreasing for the first time in a decade. The first five months of 2005 already have seen a 20% drop in China's imported PP and a 6% fall in PE. Imports of LDPE in particular have tumbled 36% compared with a year ago. These figures are surprising, given that China's PE and PP demand has grown at averages of 12.7% and 14.9%, respectively, for the past 10 years. However, Chinese domestic production capacity has grown slightly faster than demand during the same period. By 2004, China's PE output had quadrupled to 8.82 billion pounds, compared with 2.2 billion pounds in 1995, and, at a similar rate, PP output has risen to 9.92 billion pounds. Meanwhile, demand is cooling. During the past decade, China's polyolefin demand has surpassed its GDP by an average of 1.6 times. CMR projects a 5-7% growth rate from 2005 through 2015, staying lower than GDP growth.

Granulating and shredding has long been accepted as a way to reclaim material, but many processors fail to purchase the right system or misuse the equipment they have. An effective size reduction system, with the right equipment and smart controls can be an effective way to save money on materials. The physical size, shape and throughput necessary will dictate what size granulator to buy, not the type of resin the company is grinding. However, the type of resin does play a part when grinding abrasive material like glass-filled nylon, or anticipating grinding such materials in the future. Materials handling, feeding the granulator and evacuating the grinder are also important points to consider.

China's areas of innovation align strongly with those offering the highest global growth: automotive; domestic appliances and personal computers; medical; and telecommunications. This makes it an attractive proposition for an ambitious foreign plastics producer wanting to tap into the new age of Chinese consumerism. To what extent China's innovation expertise will benefit foreign companies largely depends on their ability to work with Chinese players in joint ventures, to overcome the problems associated with intellectual property rights and issues of business culture.