| As a hydrophilic and biodegradable polymer,polyvinyl alcohol(PVA)has shown wide and potential application in biomedical materials.However,the main drawbacks,such as bad waterproof and poor mechanical properties,seriously limit its application.Therefore,more efforts should be done to overcome the drawbacks and improve the development of products.The thesis is divided into three parts as following,in which the aim is to fully utilize the value of PVA by modifying the structure.(1)We present the synthesis and characterization of the novel type of Montmorillonite(MMT)with a new type of cationic Gemini surfactant and anionic surfactant sodium dodecyl sulfate(SDS)by ion exchange.The analysis,such as FT-IR,TG,X-ray diffraction,show that the synergism of Gemini-SDS mixed surfactant system have provided higher intercalation ability than single surfactant.And the d-spacing of MMT reached 3.75 nm,which is varied from different portion of anionic and cationic surfactants.The obtained organic modified MMT will be used in the next study on the synthesis of PVA/MMT composite film.(2)The PVA/MMT film was prepared by the mixed of PVA and MMT solution and scraped film by plate.The structure and properties of the composite film were characterized by FTIR,X-ray,tensile test and water resistance test.The results showed that,compared with the pure PVA,the tensile strength of PVA/MMT composites film reached 47.63 MPa with MMT content of 1%.The stability,mechanical properties and water resistance of the composite film are improved,and MMT successfully combined with PVA molecules with good crystallization.(3)Foam material is prepared by PVA matrix material with catalyst andcrosslinking agent,condensing with formaldehyde through physical,chemical and mechanical foaming method.The results on PVA formaldehyde absorbent sponge show that,using 25 g of PVA solution(PVA particles and water mass ratio=1:7)and 5 mL of formaldehyde as a crosslinking system,while adding 5.0 mL of pentane,5.0 mL of sulfuric acid,and putting into 60℃ oven to react for 1h after mixing evenly at room temperature,the absorbent performance of the absorbent sponge was the best.The SEM results show that the cell is uniform and connecting with each other;the density,expansion and degree of crosslinking test show that foam has excellent properties of hydrophilic and water holding. |
