Preparation And Properties Of Novel Non-isocyanate Polyurethane Resin

Polyurethane(PUs)is one of the most used polymer materials in daily life and industries.Due to its excellent weather resistance,chemical resistance,surface protection,wear resistance and other characteristics,it has been widely used in the preparation of thermal insulation materials,coatings,elastomers,adhesives,sealants and biomedical materials.Traditional polyurethanes must use more toxic isocyanates,and isocyanates are mainly made from highly toxic phosgene,caused great harm to people and the environment,other materials for the preparation of traditional polyurethanes are petroleum-based materials,which are non-renewable substances.Therefore,environmentally friendly polyurethane materials become the core of the future development in the field.Whereas it is the most promising technology to prepare environmentally friendly polyurethane from non-isocyanate route.At present,the raw materials for preparing non-isocyanate polyurethane mainly use non-renewable raw materials,and the product types and application performances needs to improve greatly,compared with the current general polyurethane.In view of the above key problems in the field,in this paper,new bio-based non-isocyanate polyurethane(NIPU)was prepared from bio-based substances as raw materials,and the preparation route design,synthesis process parameters optimization,product structure characterization and comprehensive performance evaluation of four new bio-based non-isocyanate polyurethanes resin were realized:NIPU(?)resin,NIPU(?)resin,NIPU(?)resin and NIPU(?)resin.The main works and research results are as follows:(1)Preparation and process optimization of non-isocyanate polyurethane precurs carbamate diol.Carbamate diol was synthesized from bio-based decyl diamine and Propylene carbonate.The process and kinetics of the synthesis were investigated.The optimum parameters were obtained as follows:reaction temperature 100?,molar ratio 1/2,reaction time 210 min.The yield of carbamate diol reached 99.1%.The structure of the product was characterized by FT-IR and NMR.In addition,the kinetic law of the reaction was studied by using amine value determination,and the kinetic equation of the reaction was obtained as follows:,the reaction order was 2.2,the apparent activation energy was 28.03 k J/mol,and the pre-exponential factor was 5.793 min^-1.The results provide a theoretical basis for the scale-up preparation of carbamate diol precursors.(2)Preparation and performance evaluation of NIPU(?)resin.A kind of NIPU(?)with excellent comprehensive properties was prepared by ammonia transesterification exchange melt polycondensation of starch liquefaction polyol and carbamate diol.The optimal preparing parameters were obtained as follows:reaction temperature 190?,mass ratio of aminodiol to starch liquefaction polyol 10/4,dosage of stannous octanate 3.0 wt%,reaction time 20 h,vacuum pressure-0.06 MPa,and Mn of the product is 26000.FT-IR and NMR were used to characterize the structure of the product,and its thermal stability,tensile strength,biodegradability and other properties were comprehensively evaluated.Its initial decomposition temperature is 260?,and the tensile strength is 15.2 MPa.Water absorption rate is 4.2%,solubility in toluene is 8.0%,swelling index is 46.3%,gel content is 88.2%,biodegradation rate is 49.2%,degradation rate is38.1%in alkali solution.(3)In order to improve the performances of NIPU(?)resin,another NIPU(?)resin was prepared.Firstly,a long chain polyamine was prepared from L-glutamic acid and decyl diamine,then carbmate polyol was prepared by reaction of polyamine and Propylene carbonate,and the optimal preparation parameters were investigated.Following the preparation of the NIPU(?)resin by the ammonia ester melt copolycondensation from the self made starch liquefied polyols and carbamate polyols.The optimal preparation parameters as follows:reaction temperature is 200?,mass ratio of carbamate polyols and starch liquefied polyol is 5/4,dosage of catalyst stannous octylic acid is 4.0 wt%,reaction time is 20 h,vacuum pressure-0.06 MPa,its Mn is 31800.The structure of the product was characterized by FT-IR and NMR,and its comprehensive properties were evaluated.The initial decomposition temperature is 272?,the tensile strength is up to 16.9 MPa,the water absorption is 3.1%,the solubility in toluene is 3.0%,the swelling index is 33.5%,the gel content is 95.4%,the biodegradation rate is 61.1%,and the degradation rate is 45.2%in alkali solution.(4)Preparation and property of NIPU(?)resin.It was prepared by polycondensation of itaconic acid and carbamate diol.The optimal preparation conditions were obtained as follows:reaction temperature 210?,molar ratio of carbamate diol and itaconic acid is1.2/1.0,dosage of p-toluene sulfonic acid 3.0wt%,reaction time 24 h,vacuum pressure-0.08 MPa,its Mn is 38000.It was characterized by FT-IR,NMR,TG,XRD and tensile tests.The initial decomposition temperature was 280?,the tensile strength was 17.9 MPa,the water absorption was 1.4wt%,the solubility in toluene was 2.1%,the biodegradation rate was 42.3%,the degradation rate was 45.2%in alkali solution,the swelling index was102%,the gel content was 90.1%.(5)Preparation and property of NIPU(?)resin.It was prepared by the polycondensation of itaconic acid and carbamate polyol.The optimal preparation conditions were obtained as follows:reaction temperature 210?,the molar ratio of carbamate polyol and itaconic acid is 4/3,dosage of p-toluenesulfonic acid catalyst 4.0wt%,reaction time 24 h,vacuum pressure-0.08 MPa,its Mn is 41000.It was characterized by FT-IR,NMR,TG,XRD and tensile strength test.Initial decomposition temperature is280?,tensile strength is 18.5 MPa,water absorption is 1.1wt%,swelling index is 31.4%,gel content is 97.0%.the solubility in toluene was 1.0%,biodegradation rate is 52.3%,and degradation rate is 65.2%in alkali solution.(6)Application in the preparation of Herb-plastics composites.Using NIPU(?)resin as interfacial compatibilizer and pine nut shell powder and recycled PP as raw materials,Herb-plastics composites were prepared by molding process.It was characterized by SEM,thermal stability,mechanical properties and water absorption.The results show that the maximal tensile strength,flexural strength and water absorption of the composite are 23.6 MPa,42.3 MPa and 2.6%with the addition of 5.0 wt%interfacial compatibilizer,it compared with the national standard,its performance meets the requirements of the National standard(GB/T 24508-2009).