Preparation technique and characterization of polyvinylacetate porous materials

Haitao CHANG

ABSTRACT

BACKGROUND:

How to control the diameter and distribution of void is a tough problem for the preparation of polyvinylacetate porous materials, which is lack of efficient solutions.

OBJECTIVE:

To prepare polyvinylacetate porous materials by using high internal phase emulsions as templates, and to study the effect of preparation technique on diameter and distribution of void. DESIGN, TIME AND

SETTING:

The observational experiment was performed at the Institute of Chemistry and Chemical Engineering, Taishan Medical University from March 2007 to October 2008. MATERIALS Vinylacetate was supplied by Tianjin Yongda Chemical Industry Co., Ltd. Divinylbenzene and sorbitan monooleate (SPAN 80) were provided by Aldrich Company (USA). Anhydrous calcium chloride and chlorobenzene was obtained from Shanghai No.1 Reagent Plant. Toluene was purchased from Tianjin Zonghengxing Chemical Industry Co., Ltd. 1,2-Dichlorobenzene was offered by Beijing Jingyi Chemical Plant.

METHODS:

The emulsions were obtained by adding dropwise aqueous solution of CaCl2 and potassium persulfate to the continuous phase (vinylacetate, DVB and Span80) under stirring, and then polymerization was heating by water bath in constant temperature (60 ℃). The solid foams were cut into 1 cm disciform strips and extracted with propanol for 48 hours in a Soxhlet apparatus. Solid foams were dried under vacuum at 50 ℃ to obtain polyvinylacetate porous materials. The void diameter, window diameter was observed by scanning electron microscope, the specific surface area was measured by 3H-2000Ⅱ instrument. MAIN OUTCOME

MEASURES:

The specific surface area, void diameter and window diameter of porous materials.

RESULTS:

The void diameters of the polyvinylacetate porous materials were controlled 3.3-5.2 μm with window diameters of 1.7-2.3 μm. The surface areas greater than 720 m2/g could be achieved by replacing some of the monomer phase with non-polymerizable solvent, such as toluene.

CONCLUSION:

Polyvinylacetate porous materials with tailored void diameters can be produced via optimizing the composition and processing conditions of the emulsion precursor by high internal phase ratio template method.