Structural Design And Control For Phase Change Fiber Of Macromonomer-Polyacrylonitrile Graft Copolymer

Polymer solid-solid phase change materials become the research focus of phase change materials in recent years due to its excellent physical and chemical properties such as low volume changes,the liquid does not appear in the phase transition,which is an extremely promising phase change materials.At present,the preparation of polymer solid-solid phase change materials have mainly two kinds of methods:chemical method and physical method.With Polyacrylonitrile(PAN)as matrix,polyethylene glycol(PEG)as a phase change medium,through different methods(physical method and grafting method),a phase change material with solid-solid phase change behavior were prepared,it not only solved the PEG phase change materials in phase change generated when liquid phase,material deformation,the use of restricted problem,and gives a new function of Polyacrylonitrile(PAN)with phase change,which for environmental protection,solve the problems of energy shortage and lack of resources,so as to realize the utilization of renewable resources,has the far-reaching significance.In this study,first of all,a polymer skeleton with active point was prepared through Itaconic Acid selected as the second monomer to co-polymerization reaction with acrylonitrile,and then with PEG as the working substance,solid-solid phase change materials were prepared through three different preparation methods.1)Grafting method:acrylonitrile co polymer as backbones,and MDI as chain extender,the phase change material PEG was grafted onto co polymer backbone through two steps to obtain the side-chain type solid-solid phase change materials.2)Cross-liking network method:with acrylonitrile copolymer as a matrix,MDI as the cross-linking agent,using the double end carboxyl activity of itaconic acid to prepared cross-linking network,and then blended with the polyethylene glycol,a stable form of novel solid-solid phase change materials was obtained.3)Blending method:with polyacrylonitrile as matrix,P(AN-IA)copolymer as compatibilizer,polyacryonitrile/polyethylene glycol polymer solid-solid phase change materials was prepared by solution blending.And the structures of the products,the phase transition properties,thermal stability,crystallization,crystalline morphology and phase transition were studied by IR,DSC,TGA,XRD and POM test.The results show that:1)in the grafting method,the infrared test showed that polyethylene glycol was successfully grafted onto the copolymer molecules;a grafting type solid-solid phase change materials with a certain phase change was obtained in this way;and a series of different phase change temperature and phase change enthalpy of phase change materials could get by adjusting the graft rate and molecular of PEG;and the thermal stability of the materials obtained by chemical grafting was superior to the pure polyethylene glycol phase change materials.2)In the cross-linked network method,a new type of cross-linked network composite phase change materials was prepared through the cross-linking network and phase change enthalpy is relatively large,and it also has a good heat durability and thermal stability.3)In the blending method,P(AN-co-IA)has a good compatibilizing effect on PAN/PEG blends,the thermal insulation properties of the blends is good,it has a large enthalpy,and the phase change temperature and phase change enthalpy increased with the increase of PEG content,the blends showed "solid-solid" phase change properties.In the limited times cyclic heating,the phase transition temperature and enthalpy showed no obvious change,indicating the material has good heat durability.