Modification tear resistance

It was demonstrated481 that preliminary modification of cotton fabrics by grafting with AN, butyl acrylate (BA) or lauryl methacrylate enhances the efficiency of cross-linking by dimethyloldihydroxyethylurea, i.e. increases the tear resistance, abrasion resitance and the wrinkle recovery angle of the cross-linked fabric. Fabrics based on cross-linked copolymers of cotton with poly(methacrylie acid) proved less susceptible to contamination and showed easier oil and soil release than the cloths obtained from non-modified cross-linked cotton. 

A new approach to modification of thermosetting epoxy or polyurethane systems (Plastics Technology, p. 14 (April 1994)) involves surface modified rubber or UHMW-PE particles. These particles after reaction with Cl, 0 or F allows for improved properties (toughness, tear resistance, abrasion resistance, modified coefficient of friction) in the noted thermosets. 

Many modifications of the elastomers above have been developed chiefly by copolymerization with various synthetic resins. These modified elastomers furnish the engineer with a wide selection of materials suitable for special uses. An example of a relatively new hydrocarbon rubber is a copolymer of ethylene and propylene, EPR. This rubber has outstanding resistance to ozone weathering. It has lower tear resistence and higher air permeability than Buna S (SBR), but can be lined with butyl to correct the latter property. 

Keywords surface-modification, polyurethane, rubber particles, composites, adhesion, filler, compatibility, coefficient of friction, peel tests, tear resistance. 

The carboxylated types (XNBR) contain one, or more, acrylic type of acid as a terpolymer, the resultant chain being similar to nitrile except for the presence of carboxyl groups which occur about every 100 to 200 carbon atoms. This modification gives the polymer vastly improved abrasion resistance, higher hardness, higher tensile and tear strength, better low temperature brittleness, and better retention of physical properties after hot-oil and air ageing when compared to ordinary nitrile rubber. 

Composite Particles, Inc. developed two methods of surface modification of polymeric materials which are used for materials of different shapes and compositions. Here, only the spherical, non-rubber particles are discussed. Further information is included in the section on rubber particles below. One method of surface modification is based on exposing the polymeric powder to a chemically reactive gas atmosphere which oxidizes surface groups to form OH and COOH functionalities. These functionalities are then available for reaction with the components of the matrix into which modified particles are introduced. Vistamer HD and UH are manufactured by this method from polyethylenes of different molecular weights. Two factors can be regulated here the properties of the core particle and the type and density of functional groups on the surface of these particles. Polyethylene is a material, which without this modification, will not be compatible with most systems. The surface modification allows the incorporation of the material into resins. This improves abrasion resistance, tear strength, and moisture barrier properties and reduces the fiiction coefficient. 

Objective Efficient Impact modification of mLLDPE film. Solution New modifiers based on a nonolefinic elastomer. The properties obtamable from PO film created with metallocene catalyst technology can result in consistent film materials with high toughness. Yet Impact-modification strategies can stlU be used to enhance the tear and puncture resistance of these films. And these Impact modifiers do not themselves need to be based on olefinic chemistries. 

In many applications, breathable fabrics are expected to satisfy many functional characteristics other than breathability, such as fabric tear, tensile, and peel strength flex and abrasion resistance launderability tape sealability thermo-physiological comfort, etc., and perform efficiently over the lifetime of the product. "- - Surface modification or stitching may also adversely affect the functionality of fabrics. 

Due to the diversity of their properties, which encompass elasticity, toughness, tear and abrasion resistance, and their biocompatibility, polyurethanes continue to be one of the most widely used type of biomaterials. Their propensity for chemical modification enables polyurethanes to be developed for a wide range of applications. 

Practically, all properties known for LR can be incorporated into a self-adhesive material. Such modifications include LR with enhanced oil, tear and/or heat resistance. 

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