Composites, polymer-based tensile impact

Wood-filled PVC has inferior mechanical properties because of lack of interaction. Treatment of wood filler with aminosilane improves acid-base interaction between filler and polymer to the extent that impact strength and tensile properties of composite are improved over unfilled PVC. Tensile properties of PVC were deteriorated when leather particles were used as a filler. But, after filler particles were treated with ethylene-vinyl acetate copolymer, a coating was produced on the surface of filler particles that promoted adhesion with PVC and improved mechanical properties.These are some recent examples of many applications of filler preparations to improve its interaction with PVC. 

Another classification system is based on the mode of action of the additive. A plasticizing additive produces plasticized polymers irrespective of whether the additive is of low or high molar mass. Some additives work in a reinforcing manner, although the reinforced property should always be stated. For example, the tensile strength, the impact strength, or the resistance to cold flow may be improved. Since such a classification is based on the mode of action and not on the structure, block and graft polymers are sometimes classified as blends and composites. Such polymers can exist in several phases, but they are not physical mixtures. 

Various tests and analytical methods are used for the characterisation and evaluation of the properties of vegetable oil-based polymer composites. Mechanical tests for properties such as tensile, flexural, compressive, impact, hardness and wear are carried out by a universal testing machine (UTM), and by equipment for testing impact, hardness, abrasion loss, and so on. Weather and chemical resistance tests are performed in UV/ozone, an artificial environmental chamber and in different chemical media. Water uptake and biodegradability tests are carried out by standard ASTM methods. Biodegradability and biocompatibility may be studied by the same procedure as described in Chapter 2. However, in practice only a few such studies have been performed for vegetable oil-based composites. 

Sis et al. prepared composites based on poly (lactic acid) (PLA)/poly (butylene adi-pate-co-terephthalate) (PBAT)/kenaf fiber using a melt blending method [39]. A PLA/ PBAT blend with the ratio of 90 10 wt%, and the same blend ratio reinforced with various amounts of kenaf fiber were prepared and characterized. The addition of kenaf fiber reduced the mechanical properties sharply due to the poor interaction between the fiber and polymer matrix. Modification of the composite by (3-aminopropyl)tri-methoxysilane (APTMS) showed improvements in mechanical properties, increasing up to 42.5, 62.7 and 22.0% for tensile strength, flexural strength and impact strength, respectively. The composite treated with 2% APTMS successfully exhibited optimum... 

PA-6 polymer blend. Basically, both the tensile strength and impact strength of the composites were better in the presence of PP-g-MA, which had a high acid number, than in samples without the addition of the compatibiliser. Based on the surface analysis, better adhesion was also demonstrated using scanning electron microscopy (SEM) micrographs [70]. 

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