Preparation And Properties Of Castor Oil Modified Waterborne Polyurethane

With the advancement of society,the application of polyurethane materials has developed rapidly.Polyurethane products have outstanding contributions in sealants,functional resins,and elastic fibers.Because of its unique and excellent thermal and mechanical properties,it has been widely used in many fields such as fabric finishing,petroleum and petrochemical,mechanical miners,aerospace,biomedical,and agricultural production.^[1-2]However,with the development of science and technology,more attention has been paid to environmental pollution problems and legislative requirements.^[3-4]At the same time,the world oil has been exploited and exploited recently,resulting in a sharp decline in global oil reserves.The price of raw materials has skyrocketed.Therefore,the development of green chemistry and renewable chemistry is imminent.The research on modification of waterborne polyurethane has also become a hot spot in the field of polymer synthesis chemistry in recent years.Castor oil is extracted from castor plants.Its structure contains four special groups:-OH,-COOH,C=C and-COO-.Due to the variety of functional groups present,there are many ways to modify and synthesize them.At the same time,castor oil is relatively inexpensive,easy to grow and is a plant alcohol,so the relative price of castor oil is low,easy to obtain,non-polluting,renewable,and decomposable.The ratio of bis-hydroxyl to trihydroxyl in castor oil is 3:7.The average functionality of the hydroxyl group is around 2.7.It is widely used in various industries such as coatings,adhesives,lubricants,pharmaceuticals,cosmetics,paper,rubber and agriculture.And it can be used as a soft satin to react with isocyanic acid to synthesize polyurethane to improve the thermodynamic properties of the polyurethane film.In this paper,castor oil is mainly used in the research of synthetic waterborne polyurethane raw materials.First,firstly synthesize water-based polyurethane with isophorone diisocyanate raw material,castor oil,polycarbonate diol as macromolecular alcohol,2,2-dimethylolpropionic acid as hydrophilic agent and ethylenediamine.And then modified with iron ions,to study the effect of the addition of castor oil and iron ions on the thermodynamic properties of waterborne polyurethane.The structure of the modified waterborne polyurethane proved to be successful in the synthesis of the polyurethane by FT-IR analysis.When the content of DMPA is 30%,the stability of the emulsion is optimal.At the same time,the aqueous polyurethane has good centrifugation stability and a stable storage time of seven months.The mechanical tests show that the adhesion strength and tensile strength of the polyurethane are also increased by the addition of iron ions,and the adhesion strength reaches one level.The DSC test showed that the modified waterborne polyurethane had a lower glass transition temperature,and the soft satin Tg decreased first and then rose,but was always lower than the unmodified polyurethane.The Tg of the hard segment rises first and then falls,but is always higher than the polyurethane without modification.The cytotoxicity of the modified aqueous polyurethane can reach a cell survival rate of 80%or more at a concentration of less than 100ug/m L,indicating that the aqueous polyurethane can be used at a low concentration.Through the above synthetic raw materials,the prepared aqueous polyurethane has good thermal properties and mechanical properties,has good storage stability and dispersibility,and greatly reduces the biological toxicity of the polyurethane due to raw materials,and is simple to operate.Secondly,a new type of glycol is first synthesized from diethanolamine and n-isopropylacrylamide,followed by isophorone diisocyanate,castor oil,PCDL,2,2-dimethylolpropionic acid,B₂alcohol synthesizes waterborne polyurethane.The use of castor oil as a raw material and the addition of bio-alcohol greatly reduces the toxicity of the polyurethane emulsion,and the biological group has a certain shielding effect on toxicity.The successful synthesis of this kind of B₂alcohol was characterized by FT-IR.Afterwards,the synthesis of the temperature sensitive aqueous polyurethane was verified by infrared test.By testing the particle size change of the emulsion at different temperatures,it is found that when the content of B₂alcohol is 50%,the temperature sensitivity of the aqueous polyurethane is the best,and the particle size change reaches 19.19%.At the same time,the particle size mutation is in the vicinity of 37??39?,in line with the body's body temperature range.The biocompatibility of the synthesized polyurethane emulsion was tested by cytotoxicity test(MTT).The results showed that when the concentration was lower than 150 ug/m L,the cell survival rate was above 80%,which was able to meet the standard of use.It has important application prospects in the field of biomedicine.The storage stability indicates that the prepared temperature-sensitive aqueous polyurethane emulsion has a storage stability of more than half a year,and basically conforms to the practical use standard.