Films fibril strands

Commercial spun bonded or flash spun products have been made primarily from PE plexifilamentary film-fibril strands and have typically been produced using trichlorofluoromethane as a spin agent. 

Plexifilamentary film-fibril strands of fiber-forming TPX having a tenacity of 1 p den-1 have been produced. Also blends of TPX with PE and PP can be fabricated (12). 

The recent improvements for flash spinning plexifi-lamentary film-fibril strands of a fiber forming PO consist of ... 

Utilization of a 4.7, hydrocarbon/cosolvent spin liquid with a highly reduced ozone depletion hazard as compared to the halocarbon spin liquids currently used for making such strands commercially. The resulting plexifilamentary film-fibril strands have increased tenacity and improved fibrillation compared to strands flash spun from 100% hydrocarbon spin liquids [32]. 

Usually, the molecular strands are coiled in the glassy polymer. They become stretched when a crack arrives and starts to build up the deformation zone. Presumably, strain softened polymer molecules from the bulk material are drawn into the deformation zone. This microscopic surface drawing mechanism may be considered to be analogous to that observed in lateral craze growth or in necking of thermoplastics. Chan, Donald and Kramer [87] observed by transmission electron microscopy how polymer chains were drawn into the fibrils at the craze-matrix-interface in PS films [92]. One explanation, the hypothesis of devitrification by Gent and Thomas [89] was set forth as early as 1972. 

Slit films. The films are produced through a melt extrasion process using slit dies which are subsequently slit with sharp blades. These films can be further fibrillated and broken into fibrous strands, known as a fibrillated yam. 

Keratin can be seen as a biological answer to the need for a tough plastic equivalent to nylon. As hair and fur, it is a fiber. As epidermis, it is a film, and as hoof or hom, it is tough solid. The stmcture contains fibrils, which are built from three-stranded ropes of alpha-helical chains in a coiled-coil arrangement. The fibrils are embedded in a cross-linked matrix of amorphous protein that is heavily... 

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