Preparation And Properties Of Old Corrugated Container Fiber/straw Powder Foam Molding Materials

In recent years,the restricted use of nondegradable plastics and the concept of sustainable development have limited the application and development of traditional plastic based packaging cushioning materials,resulting in environmentally friendly plant-based packaging cushioning materials becoming a hot topic in the industry.As a new packaging material,plant fiber foam buffering material not only has the good buffering performance like traditional plastic foam material,but also has the resource renew ability like paper pulp molding products.In addition,the plant fiber foam buffer material has a wide range of raw materials,simple preparation process,and environmental friendly,which has great potential in the future packaging field.However,this kind of material,which is mainly made of waste paper fiber,is easy to absorb moisture in a high humidity environment,resulting in the reduction of mechanical strength,thus affecting the buffering effect.How to improve the moisture absorption and comprehensive application performance of fiber foam buffering material is a practical problem concerned by the industry.In this paper,waste paper fiber/straw powder foam molding material was prepared through microwave foaming,with waste paper fiber and wheat straw powder as the main raw material,and adhesives,foaming agents and other additives as the auxiliary agents.On the basis of optimizing the formula of fiber foaming material by orthogonal experiment,two ways were used to improve the moisture absorption of the material:one was to modify the waste paper fiber,using different modification methods to treat the waste paper fiber,and study the effects of different amounts of modi fier and different modification methods on the properties of the fiber foaming material prepared.The second was to add fillers,using different fillers to improve the absorption of the material to the environmental water,and study the effects of the amount and type of fillers on the properties of foaming materials.The results show that:(1)Through orthogonal experimental design and comprehensive evaluation,the optimal formula and process parameters of various properties of materials are obtained as follows:pulp concentration is 16%,glycerol content is 1.5 g,waste paper/straw=12:4.The beating time is 2 min.The density of foaming material is 0.126 g/cm3,the foaming rate is 1.519,the residual strain is 11.2%,the deformation energy is 8.412×104 J/m3,the minimum buffering coefficient is 5.699,and the springback rate is 84.59%.(2)When the waste paper fiber is modified with 3%KH550 and 40%acetic acid,the foam material both show better buffering performance and resilience.After the treatment of KH550 or acetic acid and NaOH,the surface of the fibers is rough,which improves the accessibility of the fibers to the additives and is beneficial to the action and combination of the additives.The hydroxyl peak strength of the modified cellulose is weakened,and the hydroxyl peak strength of the modified cellulose is weakened the most when fibers are treated by NaOH+KH550 together,and the moisture absorption rate of the prepared foam reduces the most than the unmodified,which is 11.7%.The modification of waste paper fiber also improves the thermal stability of foaming materials,among which the modification of KH550 has a more significant effect on the thermal stability of foaming materials.(3)When the dosage of diatomite is 3 wt%and kaolin is 6 wt%,the foaming material has better mechanical strength and buffering performance.The addition of these two fillers can improve the springback rate of foaming material,which increase by 8.4%and 6.1%respectively.At the same time,the addition of both fillers can reduce the moisture absorption rate of foaming materials and improve the thermal stability of foaming materials.Among them,the addition of kaolin has a more significant effect on reducing the moisture absorption rate of foaming materials,and the maximum reduction is 11.9%,while the addition of diatomite is more favorable for improving the thermal stability.After adding the appropriate amount of filler,the internal structure of the foaming material changes little,which still has relatively dense and small pores.(4)The modification of waste paper fiber and the addition of filler can not only reduce the moisture absorption rate of foam material,but also improve the compression strength,resilience and thermal stability of the material,however,increase the material density and reduce the buffering effect to a certain extent.Among them,the use of acetic acid modification can reduce the moisture absorption,but also has little influence on the density and buffering properties of foaming materials.Compared with NaOH+KH550 modifying,adding kaolin reduces the moisture absorption rate of the material more.To sum up,the waste paper fiber foaming molding materials prepared by the optimization of the process formula have the characteristics of light weight,low density,good buffering performance and degradability,and the moisture absorption rate of foaming materials is reduced either through the modification of waste paper fiber or the addition of filler,the research results provide some reference for improving the hygroscopicity of fiber foaming materials.