Study On Preparation And Properties Of Dual-Crosslinking Polymer Based On Hemp Oil

In the recent years,the exploitation of bio-based polymer products has been paid much attention with the increasingly serious problems such as environmental pollution and shortage of fossil resources.On the one hand,biomass raw materials are abundant and renewable.On the other hand,enco-friendly polymer materials can be prepared by modifying raw materials reasonably.As an important biomass resource,vegetabl eoil contain a large number of unsaturated fatty acids,such as oleic acid,linoleic acid,linolenic acid and so on,thus it can be used to prepare many kinds of flexible polymers.However,the traditional vegetable oli-based polymer materials also have some defects,such as:insufficient rigidity,poor value,limited application field,etc.Thus,three kinds of dual-crosslinking monomers containing various reactive functional groups were synthesized using hemp oil(HO)as raw material in our work.And the dual-crosslinking polymer materials were also prepared by dual-crosslinking technology.The main research work are as follows:1.Fristly,a novel type of dual-crosslinking resin monomer(MA-AEHO)containing carboxyls and vinyls was synthesized using hemp oil(HO)as raw material by epoxidation,epoxy-ring opening and hydroxyl esterification.Analysis with FT-IR and ~1H NMR indicated its successful synthesis.Two single-rosslinking polymers and two dual-crosslinking polymers were obtained by different crosslinking processes using MA-AEHO.The properties of four different polymers were tested.Mechanical performance tests showed that for dual-crosslinking polymers,their tensile strength were significantly improved and elongation at break were decreased compared with single-crosslinking polymers,and the tensile strengths of the dual-crosslinking polymers were all above 30 MPa.Dynamic thermal mechanical analysis showed that the dual-crosslinking polymers have relatively higher energy storage modulus and glass transition temperature than single-crosslinking polymers,and the highest T_g of polymers can reach up to 91.44?.Thermogravimetric analysis results showed that these four curing polymers possessed good thermal stability,and the initial decomposition temperature of all polymers are all above 300?.2.In addition,a novel type of dual-crosslinking resin monomer(MAHHAGMA)containing carboxyls and vinyls was synthesized using hemp oil(HO)as raw material by hydrolysis,carboxyl epoxidation,epoxidation and hydroxyl esterification.Analysis with FT-IR and ~1H NMR indicated its successful synthesis.Polymerized vinyl ester single-crosslinking polymer and polymerized epoxy-vinyl ester dual-crosslinking polymer were obtained by different crosslinking processes using MAHHAGMA monomer.The comprehensive properties of two polymers were comparatively tested.The results of mechanical properties test show that the polymerized epoxy-vinyl ester dual-crosslinking polymer has relatively higher tensile strength(26.00 MPa)and shore hardness(75)than polymerized vinyl ester single-crosslinking polymer.Dynamic mechanical thermal analysis showed that the polymerized epoxy-vinyl ester dual-crosslinking polymer has relatively higher crosslinked density(381.24 mol/m~3)and glass transition temperature(55.29?)than polymerized vinyl ester single-crosslinking polymer.3.Finally,another novel type of dual-crosslinking resin monomer(HHAGE)containing carboxyls and vinyls was synthesized using hemp oil(HO)as raw materialby hydrolysis,hydroxylation of double bondsand carboxyl epoxidation.Analysis with FT-IR and ~1H NMR indicated its successful synthesis.Polyurethane-oxazolidone polymer was obtained from HHAGE.The comprehensive properties of polyurethane-oxazolidone polymer were tested.Scanning electron microscopy analysis showed that the prepared dual-crosslinking polymer formed a good crosslinked system.The mechanical properties and dynamic thermomechanical properties showed that polyurethane-oxazolidone polymer has relatively higher tensile strength(30.17 MPa),elongation at break(31.42%)and glass transition temperature(78.21?).4.The properties of four kinds of dual-crosslinking polymers were comprehensively analyzed.Compared with the single-crosslinking polymers,the prepared four dual-crosslinking polymers have higher tensile strength and crosslinking density,indicating that the prepared dual-crosslinking polymers possess excellent rigidity.The polymerized epoxy-vinyl ester dual-crosslinking polymer has the best comprehensive performance,and possessa high tensile strength and glass transition temperature.The new vegetable oil-based polymer materials prepared in this work has excellent comprehensive properties,which can greatly expand the application field of vegetable oil-based materials,and provide novel ideas for the development of other vegetable oil-based materials.Dual-crosslinking technology has great potential in the development and utilization of new bio-based products.