A screw includes a screw main body, a conveyance portion conveying a raw material, and a passage provided in the screw main body. The passage includes a first passage element, a second passage element, and a third passage element. The screw main body has a plurality of cylindrical bodies arranged in an axial direction of the rotating shaft. At least a portion of the conveyance portion is formed on outer peripheral surfaces of the cylindrical bodies adjacent to each other, and the passage is formed in the cylindrical body so as to cross over between the adjacent cylindrical bodies.

The notched Izod impact toughness and tensile elongation of poly(lactic acid) (PLA)-homopolymers are increased by about 2 to about 4 times by blending therewith a PLA-copolymer having a difunctional flexible middle segment such as a polysiloxane or a polyether from about 0.6 wt. % to about 20 wt. %. The PLA-homopolymer-PLA-copolymer blend having a difunctional flexible polymer from about 0.5 wt. % to about 10 wt. % is thermally annealed to provide impact toughness of at least about 5 kJ/m.sup.2 and tensile elongation of greater than 12%. This exceptional improvement observed in the PLA blend is a synergistic effect of the addition of the difunctional flexible polymer of the copolymer and thermal annealing. The improvement observed in the mechanical properties with high PLA homopolymer content above about 90 to about 98 wt. % is unusual and results in an increased scope of molding and thermoforming applications. The annealed PLA-copolymers having a difunctional flexible middle segment have also been found to have improved notched Izod impact properties.

The notched Izod impact toughness and tensile elongation of poly(lactic acid) (PLA)-homopolymers are increased by about 2 to about 4 times by blending therewith a PLA-copolymer having a difunctional flexible middle segment such as a polysiloxane or a polyether from about 0.6 wt. % to about 20 wt. %. The PLA-homopolymer-PLA-copolymer blend having a difunctional flexible polymer from about 0.5 wt. % to about 10 wt. % is thermally annealed to provide impact toughness of at least about 5 kJ/m.sup.2 and tensile elongation of greater than 12%. This exceptional improvement observed in the PLA blend is a synergistic effect of the addition of the difunctional flexible polymer of the copolymer and thermal annealing. The improvement observed in the mechanical properties with high PLA homopolymer content above about 90 to about 98 wt. % is unusual and results in an increased scope of molding and thermoforming applications. The annealed PLA-copolymers having a difunctional flexible middle segment have also been found to have improved notched Izod impact properties.

A co-rotating self-cleaning two-screw extruder with a gradual number of threads and through self-cleaning function, and a processing method using the same, are disclosed. The screw assembly in the extruder includes a first screw (3) and a second screw (4) that co-rotate at the same speed in engagement; the first screw (3) includes a first single threaded element, a first transition element, a multiple threaded element, a second transition element and a second single threaded element that are connected in sequence; and the second screw (4) includes a first single threaded element, a third transition element, a multiple threaded element, a fourth transition element and a second single threaded element that are connected in sequence. The materials are transferred by rotation of the first (3) and second screws (4), and get their respective compositions mixed based on the structure of a gradual number of threads; with the flow passage expanded, contracted and re-expanded in shape in sequence, the materials undergo the single-to-multiple threaded, multiple-to-single threaded and again single-to-multiple threaded chaotic mixing in sequence; and the first and second screws achieve the self-cleaning effect by wiping each other.

A co-rotating self-cleaning two-screw extruder with a gradual number of threads and through self-cleaning function, and a processing method using the same, are disclosed. The screw assembly in the extruder includes a first screw (3) and a second screw (4) that co-rotate at the same speed in engagement; the first screw (3) includes a first single threaded element, a first transition element, a multiple threaded element, a second transition element and a second single threaded element that are connected in sequence; and the second screw (4) includes a first single threaded element, a third transition element, a multiple threaded element, a fourth transition element and a second single threaded element that are connected in sequence. The materials are transferred by rotation of the first (3) and second screws (4), and get their respective compositions mixed based on the structure of a gradual number of threads; with the flow passage expanded, contracted and re-expanded in shape in sequence, the materials undergo the single-to-multiple threaded, multiple-to-single threaded and again single-to-multiple threaded chaotic mixing in sequence; and the first and second screws achieve the self-cleaning effect by wiping each other.

The invention relates to compositions comprising composite materials comprised of discontinuous fibers and one or more polymers and/or oligomers. The invention relates to methods of making the same. The composite materials can be in the form of compositions, composite sheets, laminates, pellets, and/or shaped composite products.

The invention relates to compositions comprising composite materials comprised of discontinuous fibers and one or more polymers and/or oligomers. The invention relates to methods of making the same. The composite materials can be in the form of compositions, composite sheets, laminates, pellets, and/or shaped composite products.

A method for producing a fused unplasticised polyvinyl chloride (UPVC) article (126) is provided. The method includes feeding an UPVC blend (103) into a co-rotating twin-screw extruder (100). The method further includes melting the UPVC blend (103) and conveying fused UPVC to an outlet (120) of the co-rotating twin-screw extruder (100). The method also includes collecting the fused UPVC from the outlet (120) at a rate of at least 100 kilograms/hour per litre of free volume (124) of the co-rotating twin-screw extruder (100).

A method for producing a fused unplasticised polyvinyl chloride (UPVC) article (126) is provided. The method includes feeding an UPVC blend (103) into a co-rotating twin-screw extruder (100). The method further includes melting the UPVC blend (103) and conveying fused UPVC to an outlet (120) of the co-rotating twin-screw extruder (100). The method also includes collecting the fused UPVC from the outlet (120) at a rate of at least 100 kilograms/hour per litre of free volume (124) of the co-rotating twin-screw extruder (100).

A multiple screw extruder (50) combines application of vacuum to a vacuum vent (62) positioned between material feed locations (70, 72) of the extruder and use of specially configured extruder screws (58) to extract gases, primarily air, out of the extruder to densify the materials introduced into it and to extract unwanted fluid from material introduced for mixture with molten polymeric material flowing through the extruder. The multiple screw extruder is operationally versatile in that it is capable of carrying out the material densification and fluid extraction processes either separately or simultaneously. Implementation of the disclosed vacuum feed technology provides an increase in rate of extrudate throughput as compared with that achievable by implementation of atmospheric venting (16) in a conventionally configured extruder (10a, 10b).