The Physics-Mechanical and Morphological Properties of Cellulose-Filled Polystyrene (PS) and Polyvinyl Acetate (PVAC) Blends.
Abstract
Studies of physico-mechanical and morphological properties of pure and a-cellulose reinforced blends of polystyrene (PS) and poly (vinyl acetate) (PVAc) are reported in this work.
The compression moulded articles of the blends of different compositions (10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20 and 90:10, PS/PVAc) were tested for mechanical perform65uance, absorption behaviour, void activity and morphological arrangements.
Comparison of mechanical properties such as tensile strength, modulus of elasticity and elongation at break revealed apparent compatibility domains for 20:80 and 10:90, PS/PVAc for both pure and reinforced blends.
However, the a- cellulose filled blends have enhanced tensile strength for all the compositions.
From the values of the breaking load (in kilonewtons- KN) Vs composition of the blends, there was considerable strength improvement with a-cellulose filler content.
The equilibrium sorption in four different solvents, showed a declining order in accordance to acid > water > base > acetone.
However, solvent absorption increased with filler content in all the solvents, because the filler increased the gelation level, hence the sorption rise except in acetone which showed a sharp reduction in % absorption in the presence of a-cellulose filler.
Introduction
1.1 Background of Study
Blending procedures had been employed since time immemorial. The principle of blending is geared towards achieving property averaging.
dA blend is therefore the physical mixture of two or more substances, without a chemical Linseed oil, a triglyceride of unsaturated fatty acids, is heated with a brittle resin, usually an unsaturated C20 mono carboxylic acid (Mantell, Kopf, Curtis and Rogers, 1942).
The resin itself could be used as a coating, but the linseed oil is incorporated to reduce the brittleness of the product. On the other hand, the linseed oil by itself forms an oily, slow-to-harden coating.
Thus, the principle of property averaging (blending) was recognized a long time ago. The resin contains unsaturation and, presumably during the heating with the oil and the subsequent oxidative cross-linking, is incorporated covalently.
Nevertheless, no segregation occurs and clear, tough, films of high molecular weight result. Many modern vanishes use phenol-formaldehyde resins rather than natural resins.
Modification of the basic phenol structure is required in order to obtain solubility of the resin in the linseed oil.
Parasubstitution with tert-butyl, phenyl, and other hydrocarbon groups increases the aliphatic character (reduces solubility parameter) enough to achieve solubility.
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