Effect Of Hydrolysis Solution Of Polyacrylonitrile Fiber On Properties Of Sodium Silicate Sand

Foundry sodium silicate sand has the advantages of less pollution, safe working conditions and so on, so it is considered to be the most likely to realize the green environmental protection casting process. But the poor collapsibility of sand, difficult to recycle etc, these defects restrict its the use of promotion. In this paper, sodium silicate sand as the research object, it is modified to improve its comprehensive properties, convenient for its popularization and application.In this paper, the hydrolysis solution of polyacrylonitrile fiber is used as the modifying agent of sodium silicate sand. Study on the pressure hydrolysis process of polyacrylonitrile fiber. Experimental results show that, under the conditions without catalyst, hydrolysate is added amount of sand 4 %, the reaction temperature is 190-195 degrees celsius, the time is 7 hours, the bath ratio is 6, the tensile strength of the sample to achieve the best value, is 2.37 MPa,at this time, the polydispersity of the hydrolysis solution is about 1.2, and its stability is good. If the catalyst is added, the reaction time can be shortened to 3hours, and when the amount of catalyst is 0.7 %, the tensile strength of the sample reached the maximum value, is 1.89 MPa.In this paper, the polyacrylonitrile hydrolysate obtained by the optimum hydrolysis process is used as the modifier, modified sodium silicate is added 4 %amount of sand. And then through the performance test, scanning electron microscopy, X- ray diffraction analysis, infrared spectrum analysis, the effect of different additives on the properties of sodium silicate sand is studied systematically. Experimental results show that, the fluidity of No.1 modified sodium silicate sand reaches the maximum value of the test when the content of the modifier is 40 %, which is 48.51 %. Collapsibility reaches the minimum value of the test when the content of the modifier is 10 %, which is 0.09 MPa.The tensile strength of 24 hours reaches the maximum value of the test when themodifier content is 40 %, which is 0.184 MPa. The immediate tensile strength reaches the maximum value of the test when the content of the modifier is 0 %,which is 0.093 MPa. The fluidity of No.2 modified sodium silicate sand reaches the maximum value of the test when the content of the modifier is 10 %, which is51.8 %. Collapsibility reaches the minimum value of the test when the content of the modifier is 40 %, which is 0.14 MPa. The tensile strength of 24 hours reaches the maximum value of the test when the content of the modifier is 30 %, which is0.223 MPa. The immediate tensile strength reaches the maximum value of the test when the content of the modifier is 10 %, which is 0.096 MPa.In this paper, the sodium silicate sand used in the actual production of a certain factory is modified by the hydrolysis of polyacrylonitrile hydrolysate obtained by the optimum hydrolysis process. The modified sodium silicate sand can meet the strength requirements, as well as effectively improve the fluidity and collapsibility of sodium silicate sand. The results show that the hydrolysate of polyacrylonitrile fiber as modifier can effectively improve sodium silicate sand mobility and collapsibility, it is feasible to select the modifier.