| Recently,extensive use of plasticizers and environmental concerns make people pay great attention to the toxicity of plasticizers.Phthalates,which take up 90% of the total plasticizers usage,are by far the most widely used plasticizers.However,these phthalate plasticizers are reported harmful to human immune and reproductive systems,and have potential risk to cause cancer.Many countries have set up laws to regulate phthalates use.Extensive research are being carried out to develop phthalate free plasticizers which are nontoxic,environmental friendly,and renewable.Cardanol,a phenol derivative bearing a C15 unsaturated side chain at the meta-position extracted from cashew nut shell liquid(CNSL),is a non-edible by-product of CNSL industries.The intrinsic structure,low cost,and easy access make it possible to be widely used for chemical modification and functionalization.In this thesis,epoxidized plasticizers obtained from cardanol and their plasticizing effects of PVC are studied.1.Cardanol,an agricultural by-product of industrial processing from cashew,is used to synthesize epoxidized cardanol laurate(ECDL)plasticizer.The target product is characterized using FTIR,1H NMR and 13 C NMR.Plasticizing effect of ECDL substitution for petroleum-based plasticizer dioctyl phthalate(DOP)in soft poly(vinyl chloride)(PVC)was investigated using dynamic mechanical analysis(DMA),thermogravimetric analysis(TGA)and mechanical testing,and compared with PVC incorporated commercial epoxidized soybean oil(ESBO).When DOP was substituted by 33.3% of EDCL,there is a slight increase of 5% in glass transition temperature(Tg),and a maximum increase of 14.55% for the elongation at break.In addition,scanning electron microscopy(SEM)reveal that morphology of blend plasticized by DOP incorporated with ECDL is finer and more homogeneous compared to blend plasticized by neat DOP or ESBO.Compared with DOP/PVC,TGA results show that the initial degradation temperature(Ti),the 50% weight loss temperature(T50),and the first peak decomposition temperature(Tp1)of ECDL/PVC increase by 16.8,26.5 and 7.1°C,respectively.Moreover,plasticizing system with ECDL posses longer stability time,lower volatility,lower exudation loss and higher chemical resistance than that of DOP.Therefore,as an environmental-friendly and renewable bio-based plasticizer,ECDL can partially replace DOP.2.A new type of plasticizer of epoxidized cardanol butyl ether(ECBE)is synthesized via Williamson etherification and epoxidation.Successful result is confirmed by FTIR,1H NMR and 13 C NMR.The obtained product is added to PVC incorporated with DOP for evaluation.The mechanical and thermal properties of the PVC films are studied by tensile test,TGA,and DMA.The processability,migration,and volatility of the plasticizing systems are also investigated.Tensile tests show a maximum increase in elongation at break of 17.8% in the PVC films.DMA results indicate Tg shift toward lower temperatures.TGA results reveal that PVC blends with higher content of ECBE have higher thermal stability;Ti,T50,and Tp1 increased by 15.3,14.8 and 4.1 ℃,respectively.Processing time is extended from 11.56 to 59.94 min.The plasticizing performance of migration and volatility resistance are higher than that of neat DOP.When the content of ECPP is 30wt%,PVC plastic shows better integrated properties.3.A novel plasticizer containing phosphorus based on cardanol(ECPP)is obtained by esterification and epoxidation.The structure of ECPP is studied by FTIR,1H NMR and 31 P NMR.Then,a series of PVC blends are prepared using different weight ratio of DOP and ECPP as corporate plasticizers.Mechanical property,thermal decomposition behavior and flame retardant property are systematically studied by tensile tests,TGA,TGA-FTIR,TGA-MS,LOI and DMA.When DOP is substituted by ECPP,elongation at break has a slight change.TGA results show that Tg slowly increase from 41 to 51.36 ℃,Ti,T50,Tp1 and Tp2 are increased from 245.8,300.8,293.4 and 456.8 ℃ to 260.1,320.2,299.2 and 473.2 ℃,respectively.TGA-FTIR detect that the main gases escape from degradation process are H2 O,CO,HCl,CO2 and C6H6.TGA-MS reveal that the masses of CO,HCl,CO2 and C6H6 released from F4 are less than that of F0,but the mass of H2 O released from F4 are more than that of F0.Therefore,ECPP can partiallly substitute DOP as green flame retardant plasticizer. |
