Abstract: The present invention provides novel hybrid self-reinforced composites, combining an oriented brittle fibre and an oriented thermoplastic polymeric ductile fibre (as reinforcement phase) in the same thermoplastic polymeric matrix phase. The hybrid self-reinforced composites are strong and stiff, but in case of impact or crash they have high strain to failure and absorb a lot of energy. The present invention also relates to methods to produce said hybrid self-reinforced composites by a hot compaction technique.

Abstract: The present invention provides novel hybrid self-reinforced composites, combining an oriented brittle fibre and an oriented thermoplastic polymeric ductile fibre (as reinforcement phase) in the same thermoplastic polymeric matrix phase. The hybrid self-reinforced composites are strong and stiff, but in case of impact or crash they have high strain to failure and absorb a lot of energy. The present invention also relates to methods to produce said hybrid self-reinforced composites by a hot compaction technique.

Abstract: A process of production of a monolithic article from a web of fibres of oriented polypropylene polymer, comprising the steps of subjecting the web to elevated temperature and pressure sufficient to melt a proportion of the polymer and compact it, and then cooling the compacted web, wherein an accelerated rate of cooling is employed down to 100° C. The process is of particular benefit when the weight average molecular weight (Mw) of the fibers is 250,000 or below. The resultant articles have good stiffness and strength, yet with reasonable ductility. Similar articles cooled slowly are brittle.

Abstract: A process for production of a monolithic article from a web of fibres of oriented polypropylene homopolymer or copolymer having a weight average molecular weight (MW) of at least 250,000 includes the steps of subjecting the web to elevated temperature and pressure sufficient to melt a proportion of the polymer and compact it, and thereby yielding an oriented phase and a matrix phase, and effecting a heat treatment selected from (i) subjecting the compacted web to a retarded rate of cooling down to a lower temperature at or below the temperature a which the recrystallisation of the matrix is complete; and (ii) annealing the compacted web at an annealing temperature within 15° C. of the temperature at which the matrix phase is completely melted. The resultant articles have good stiffness and strength, and acceptable ductility, yet corresponding articles made with polypropylene of lower Mw are brittle.

Abstract: Method of producing an article comprising providing a raw material in the form of a plurality of polymer elements, the polymer elements comprising an amorphous polymer; heating the materials to a temperature above a first predetermined temperature; and compacting the material whilst above the first predetermined temperature. The first predetermined temperature is the Tg of the polymer elements, the pressure is between 100 and 200 psi; and the temperature and pressure of compaction are sufficient to soften the outer portion of the polymer elements and to cause the polymer elements to bonds to each other without melting or softening of the inner portion of polymer elements. A product is produced having a structure which comprises cores of amorphous polymer that have not been softened or melted in the method, surrounded by a mass of softened and re-hardened material which bonds the cores together.

Abstract: A process for production of a monolithic article from a web of fibres of oriented polypropylene polymer, comprising the steps of subjecting the web to elevated temperature and pressure sufficient to melt a proportion of the polymer and compact it, and then cooling the compacted web, wherein an accelerated rate of cooling is employed down to 100° C. The process is of particular benefit when the weight average molecular weight (Mw) of the fibres is 250,000 or below. The resultant articles have good stiffness and strength, yet with reasonable ductility. Similar articles cooled slowly are brittle.

Abstract: The present invention provides an amorphous polymer article produced by hot compaction and a method of producing the same. The article is heated to a temperature and maintained at a pressure sufficient to cause softening of the polymer strands to sufficient a degree to allow bonding to adjacent fibres to take place without actually transforming the polymer into a liquid state.

Abstract: Process for the production of a homogenous polymeric monolith wherein an assembly of oriented thermoplastic polymer fibres is maintained under a contact pressure sufficient to ensure intimate contact at an elevated temperature high enough to melt a proportion of the polymer. The assembly is subsequently compressed at a compaction pressure higher than the contact pressure while still being maintained at the elevated temperature. The resulting polymeric products are useful, for example as orthodontic brackets, bone prostheses and in body armor.