Tworzenie się nanowłókien polipropylenowych w wyniku deformacji w stanie stałym podczas mieszania ze stopionym polietylenem

A novel method for preparing all-polymer nanocomposites was described. The technique is based on enhanced susceptibility to deformation of a polymer having a lowered number of entanglements in the amorphous phase. Polymer powder remaining in the solid state was blended with a second molten polymer, and the shearing forces during compounding deformed the powder grains into nanofibers. After solidification of the matrix all-polymer nanocomposite was obtained. The effectiveness of the method was demonstrated on the example of ultra-high molecular weight polyethylene (PE-UHMW) composite containing PP nanofibers, produced in situ during compounding.Opisano nową metodę otrzymywania nanokompozytów w pełni polimerowych (z ang. all-polymer). W metodzie tej wykorzystuje się zwiększoną zdolność do odkształcania polimeru mającego ograniczoną liczbę splątań w fazie amorficznej. Polimer w stanie stałym miesza się z drugim stopionym polimerem, a siły występujące podczas mieszania powodują przekształcanie się ziaren stałego polimeru w nanowłókna. Po zestaleniu matrycy powstaje w pełni polimerowy nanokompozyt. Skuteczność metody pokazano na przykładzie kompozytu polietylenu o bardzo dużym ciężarze cząsteczkowym (PE-UHMW) zawierającego nanowłókna polipropylenu (PP) wytworzone in situ w procesie mieszania

Badania przetwórstwa stopowego biodegradowalnych poliestrów alifatyczno-aromatycznych na wyroby włókniste

Research is described in the article concerning the melt processing of biodegradable aliphatic-aromatic copolyesters into fibrous products. Copolyesters containing 57 - 60% of a tri-component aliphatic portion (copolymers of butylene glycol and adypic-, succinic-, glutaric acid and terephtalic acid) prepared on a large laboratory scale were used in fibres and nonwoven from molten polymers. Fibres were made in a two-step process comprising spinning and drawing. Nonwovens were formed by the spunbond method. Main properties are given of the polymers and fibres, and the nonwoven made thereof. It was found that the aliphatic-aromatic copolyesters prepared reveal good spinability. Thermal properties: Tg g < 0 °C oraz niską T m ~115 °C włókna z alifatyczno-aromatycznych kopoliestrówmogą być stosowane w ograniczonym zakresie, przede wszystkim na wyroby jednorazowego użytku. Ze względów ekonomicznych bardziej wskazany jest przerób tych polimerów na gotowe wyroby włókiennicze, np. włókniny spun bonded

Recent developments in nanocellulose-based biodegradable polymers, thermoplastic polymers, and porous nanocomposites

International audienceNanocellulose has generated a great deal of interest as a source of nanometer-sized reinforcement, because of its good mechanical properties. In the last few years, nanocellulose has also attracted much attention due to environmental concerns. This review presents an overview of recent developments in this area, including the production, characterization, properties, and range of applications of nanocellulose-based biodegradable polymers, thermoplastic polymers, and porous nanocomposites. After explaining the unique properties of nanocellulose and its various preparation techniques, an orderly introduction of various nanocellulose-reinforced biodegradable polymers such as starch, proteins, alginate, chitosan, and gelatin is provided. Subsequently, the effects of nanocellulose on the properties of thermoplastic polymers such as polyamides, polysulfone, polypropyrol, and polyacronitril are reported. The paper concludes with a presentation of new finding and cutting-edge studies on nanocellulose foam and aerogel composites. Three different types of aerogels, i.e., pristine nanocellulose-based aerogels, modified nanocellulose-based aerogels, and nanocellulose-based templates for aerogels, are discussed, as well as their preparation techniques and properties. In the case of foam composites, the research focus has been on two major preparation techniques, i.e., solvent-mixing/foaming and melt-mixing foaming, their respective challenges, and the properties of the final composites. In some cases, a comparison study between cellulose nanocrystals and cellulose nanofiber-reinforced biodegradable polymers, thermoplastics, and porous nanocomposites was carried out. Considering the vast amount of research on nanocellulose-based composites, special emphasis on such composites isprovided at the end of the review