Study On Water-Resistant Of Biodegradable PVA Films

Poly(vinyl alcohol) (PVA) is the largest synthetic watersoluble polymer produced in the world.It is also a versatile polymer with many industrial applications because of its biodegradability, biocompatibility, environment-friendliness, chemical resistance, and excellent physical properties. Recently for the special requirements of water resistance ability, the development of PVA film has a new research direction.PVA is a hydrophilic biodegradable polymer which is mainly composed of C-C bonds. However, its water solubility is related to its degree of hydrolysis, molecular weight, and the modification while blending with other processing additives, with a maximum value at the degree of hydrolysis of 88%. The main shortcomings of biodegradable starch/PVA film are hydrophilicity and poor mechanical properties. This paper has done the receach on molding PVA flim to overcome the main shortcomings. At the same time, the influence of adding accessory ingredient, such as glycerin, agent A and so on, on the PVA flim has been studied.At present,the study of PVA blow molding film is blow out after adding plasticizer to PVA,then analyzed the influence of plasticizer on performance of PVA film. In this paper, under the premise of maintaining certain mechanics performance of PVA film, PVA film is studied after adding different ratios' starch,glycerin, agent A and TDI. For example, the influence of the content of TDI and agent A in different systems on mechanical property of PVA film is studied.At the same time the influence of different processing technic on properties is investigated.Experimental results indicate that:When the content of other ingredients in system are unvaried, with glycerin increasing, tensile strength and tearing strength of PVA blow molding film reduce, but broken extending rate increases. Agent A and PVA can be compatible excellently. The mechanical property of film decreases along with the increasing amount of agent A which was added in alone. To the contrary, the water-resistence increases along with the increasing amount of agent A. The mechanical property of film increases unconspicuous while the water-resistence significantly improved compared to the previous. In a conclusion, the optimum condition is as follows:PVA 100, glycerin 40, agent A 20,TDI 1, the tensile strength is 25.6 MPa, and tearing strength is 64.2 MPa, and wet strength of the film is around 20 MPa. Furthermore adding an amount of agent A and TDI could improve effectively the water-resistence of PVA film.