Preparation And Properties Of Eucommia Ulmoides Gum Functional Composites

With the rapid development of rubber industry,the consumption of rubber has increased significantly,and it has become more and more important to seek a substitute resource for rubber.Eucommia ulmoides gum(EUG)is a degradable,renewable,resource-rich natural polymer,which is the isomer of natural rubber.It has the characteristics of wear resistance,water resistance,acid resistance,alkali resistance,and good thermoplasticity.Based on the excellent physicochemical properties of Eucommia ulmoides gum,this paper developed a variety of construction strategies and control methods for functional composite materials,and the synergistic mechanism of Eucommia ulmoides gum and its derivatives with organic/inorganic fillers were systematically explored.The comprehensive properties of functional composites were improved through component regulation and structural design,which provided experimental basis and theoretical support for the realization of high-value,diversified and functional utilization of Eucommia ulmoides gum.The main contents are as follows:(1)In order to solve the problems of unsatisfactory mechanical properties and poor aging resistance of natural EUG material,EUG and polycaprolactone(PCL)were physically modified.EUG/PCL composite film was prepared by layer-by-layer casting process.The composite film has good mechanical properties(32.7 MPa,514.3%),thermal stability,water vapor barrier(0.49 × 10-13 g·cm·cm-2·s-1·Pa-1),soil degradation and aging resistance,which has a certain application potential in the field of packaging and other barrier materials.(2)In view of the problems of poor mechanical properties and poor corrosion resistance of traditional electromagnetic shielding materials,PCL/EUG composite materials has good acid and alkali resistance,mechanical properties,and light materials in the last research work,which is used as flexible matrix materials of shielding materials.Introducing carbon-based conductive fillers,a lightweight and degradable EUG-PCL/rGO-CNTs nanocomposite film was developed by hot pressing.The 1D CNTs and 2D rGO fillers produce a synergistic effect,forming a complete electrical and thermal conductivity network.The thermal and electrical conductivity of EUG-PCL/rGO-CNTs nanocomposite films are greatly improved,and the related mechanisms of the enhancement are discussed.In addition,the feasibility of the product was determined by using the thermal properties,mechanical properties,physical and chemical damage resistance of the composite material,and the relationship between the content of filler and the properties of the composite film was discussed.The EMI shielding effectiveness of the composite film was 43.5 dB.This study provides a new idea for the preparation of EUG-based nanocomposites and broadens the practical application of EUG materials in the field of conductive gaskets.(3)In order to solve the problems of poor compatibility between EUG and other organic/inorganic materials and less reactive groups,epoxidized Eucommia ulmoides gum(EEUG)with different epoxidation degrees was prepared from EUG.With the increase of epoxy groups,the transparency,glass transition temperature,thermal stability,and the polarity of EEUG increase,and the crystallinity decreases.The EUG changed from a hard plastic state to an elastic state,showing more rubbery characteristics.In order to solve the problems of low UV resistance and low tensile strength of EEUG,a novel UV blocker silica-graphene oxide(SiO2-GO)was developed.The SiO2-GO inorganic material was introduced into EEUG by electrostatic spinning process to prepare EEUG/SiO2-GO(EE/SG)nanocomposite film.The GO and SiO2 provide multiple protection to the substrate through physical barrier effects and UV absorption scattering.At the same time,the interaction between EEUG and SiO2-GO significantly improved the UV protection coefficient of the film,showing better UV blocking performance(UPF=18.8).As the thickness increases,the UV protection performance also increases(UPF=26.0).This study provides a feasible strategy for the efficient UV resistance of EUG,which is expected to provide new ideas for the preparation of bio-based multifunctional barrier materials.(4)In view of the problems of complex preparation,high cost,and environmental pollution of inorganic materials used in the above study,this section adopts lignin(EHL)and EEUG to prepare EEUGEHL composite film by hot-pressing strategy to build high-performance intelligent materials.EHL is not only used as a crosslinking agent to cure EEUG,but also as an enhanced filler to improve the mechanical properties(24.5 MPa,1097.5%),oil resistance,and hydrophobicity(94.5°)of composite.In addition,EEUG-EHL composite film showed good shape memory(shape recovery rate up to 96.0%),self-healing,and recyclable properties of EEUG-EHL composites.The physical-chemical crosslinking between EHL and EEUG as well as the binding and strengthening mechanism of EHL on EEUG molecular chain were further studied.This study provides a method for the intellectualization of EUG,and also provides a direction for the high-value utilization of lignin.(5)The EEUG-EHL composite explored in the above section shows good adhesion,mechanical properties,aging resistance,and other properties.Therefore,in this study,EEUG-EHL is used as the matrix material.The zeolite imidazolium ester skeleton material(ZIF-8)and corrosion inhibitor 8hydroxyquinoline(8HQ)(8HQ@ZIF-8 nanocontainer)are introduced into EEUG-EHL matrix.A novel self-healing EEUG-EHL/8HQ@ZIF-8 composite coating with pH response was developed by wire rod coating process.The composite coating has good adhesion,hydrophobicity,and thermal stability.The corrosion resistance of the composite coating was evaluated by using EIS method and salt impregnation method.The results showed that the impedance modulus of the composite coating reached 107 ohm cm2 after soaking for 15 days,and the sample was immersed in salt solution for 432 h to produce less corrosion.Under the synergistic effect of ZIF-8,8HQ and EEUG-EHL matrix,the composite coating has good anticorrosion performance.(6)In view of the defects of the monolayer coating studied in the last section,which are more likely to cause the corrosive medium to pass through the coating and reach the metal base,resulting in corrosion reaction.This section adopts the bottom-up assembly method to prepare the superhydrophobic multilayer coating to achieve multiple protection.As the bottom layer of multilayer coating,EEUG-EHL has excellent adhesion,mechanical strength,permeability resistance,and corrosion resistance.The intermediate layer is a complex of 8HQ@ZIF-8 nanoparticles and EEUG-EHL matrix,and the controlled release of corrosion inhibitor 8HQ is realized through pH response,with self-healing properties.Inspired by the micro-nano structure of cicada wings,fluorosilane(FAS)-modified ZIF-8 nanoparticles(fZIF-8)were sprayed to fabricate a micro-nanostructured surface with good superhydrophobicity(CA>150°,SA<5°),chemical stability,self-cleaning,anti-fouling,anti-pollution,and anti-corrosion properties(45 d,the impedance modulus of 108 ohm cm2)of multilayer coatings.