Research On Preparation Technology Of Salix Fiber-based Lightweight Engineering Material

A kind of lightweight engineering material was developed in this paper by using Salix fiber which is a kind of local advantage resources, produced from the Inner Mongolia western in order to open up a new way of Salix resource utilization. It were analyzed the basic principle of materials form and the selection principle of raw materials, studied different alkali treatment conditions on the influence of the relative contents of hydrogen bonds and crystallinity of the fiber, optimized the preparation technology of materials by using the response surface method, and studied the effect of melamine resin reinforced material, the main contents are as follows:1. The different alkali treatment conditions were selected that the alkali concentration was 0 g·L-1,10g·L-1,20g·L-1, 30g·L-1,40g·L-1,50g·L-1,60g·L-1,alkali treatment time was 0.5h, 1.0h,1.5h,2.0h,2.5h,3.0h, alkali treatment temperature was 20℃,40℃,60℃,80℃,100℃; It was studied that the different alkali treatment conditions on the influence of the crystallinity and hydrogen bond relative content of fiber, the following conclusions:(1) The crystallinity of Salix fiber first increases then decreases with the increase of alkali concentration, and maximum is 42.69% when alkali concentration is 10g·L-1; The variation trend of the content of intermolecular hydrogen bond O(6)H...O(3’) and crystallinity is consistent, the variation trend of the content of intramolecular hydrogen bond O(3)H...O(5) is contrary to O(6)H...O(3’), and the content of intramolecular hydrogen bond O(2) H...O(6) is almost the same.(2) The crystallinity of Salix fiber first increases then decreases with the increase of alkali treatment time, and maximum is 40.23% when alkali treatment time is 2h; The variation trend of the content of intermolecular hydrogen bond O(6)H...O(3’) and crystallinity is consistent, the variation trend of the content of intramolecular hydrogen bond O(3)H...O(5) is contrary to O(6)H...O(3’), and the content of intramolecular hydrogen bond O(2) H...O(6) is almost the same.(3) The crystallinity of Salix fiber increases with the increase of alkali treatment temperature; The variation trend of the content of intermolecular hydrogen bond O(6)H...O(3’) and crystallinity is consistent.the variation trend of the content of intramolecular hydrogen bond O(3)H...O(5) is first stable then gradually decreases, and the content of intramolecular hydrogen bond O(2) H...O(6) is almost the same.2. The experiment design made use of the center of the Box-Benhnken combination experiment Design principle in the Design-Expert. V8.0.6.1 software, which the factors are Salix fiber and PVA, foaming agent and sodium silicate, the response value are density and compressive stress, the following conclusion:(1) The quadratic polynomial model has been established that is about between response value density and compressive stress with the four factors.(2) Using single factor response analysis, With the increase of Salix fibre content the density of the material increased gradually, the compression stress first increases then decreases; With the increase of PVA concentration, the density is gradually increased, the compression stress first increases then decreases; With the increase of foaming agent content, the density and compression stress decrease; With the increase of concentration of sodium silicate, the density and compression stress first increase then decrease, but the change is not large.(3) When it chose the minimum density and the maximum compressive stress, the results showed that the optimal Salix fibre content is 38g, PVA concentration is 8%, foaming agent content is 4g and sodium silicate concentration is 4%. the density is 0.0412 g·cm-3 and the compressive stress is 8.976 KPa under the optimal conditions.3. Salix fiber-based lightweight engineering material were prepared by mechanical foaming method,chemical foaming method and a sol-gel method; The effects of adding various amount of melamine resin on the density, compressive stress, oxygen index, heat stability and the internal chemical bonds of the material were also studied. The results showed as follow:(1) The density, compressive stress and oxygen index of material were heighten along with the increase of melamine resin content.(2) The absorption peak of hydroxy and conjugated carbonyl were weaken with the addition of melamine resin in infrared spectrum analysis.(3) The thermal stability of materials at higher than 340℃ was improved and increases along with the increase of melamine resin content in thermogravimetric analysis.(4) The endothermic reaction at 345℃ and the exothermic reaction at 420℃ were suppressed, namely the flame retardant effect was produced, and the flame retardancy was reinforced with the increase of the amount of melamine resin in differential scanning calorimetry analysis.