Synthesis And Performance Of Castor Oil-based Flame Retardant Plastic Plasticizers

Poly(vinyl) chloride(PVC) plastics with high yield has been widely used in China. The use of phthalate plasticizers such as dioctyl phthalate(DOP), with reproductive toxicity and flammability reduced flame retardant properties, restricted the application range of PVC plastics. Development of environmentally friendly flame retardant plasticizer is an important direction of PVC plastic plasticizer. In the previous study, a series of diethyl phosphate flame retardant plasticizer, 9,10-dihydro-9-oxa-10-phospha phenanthrene-10-oxide(DOPO) groups containing plasticizer, chlorinated phosphate, nitrogen and phosphorus synergistic flame retardant plasticizer, DOPO groups and 1,3,5-Tris(2-hydroxyethyl)cyanuric acid groups containing reactive plasticizers derived from castor oil were synthesized. In addition, flame retardant polymeric poly(vinyl chloride) materials modified with flame retardant plasticizer based on caster oil was successfully synthesized by “Click Chemistry”. Property of PVC products plasticized with these plasticizers was studied with LOI, TGA, SEM, TGA-FTIR,TGA-MS and Cone.1. A flame retardant plasticizer based on castor oil(PPC) was synthesized from castor oil by epoxidation reaction and ring opening reaction with diethyl phosphate. Flame reatrdant PVC blends were prepared using PPC and DOP as mixing plasticizer. The melting behavior,thermal property, flame retardant performance, flame retardant mechanism and mechanical property of PVC blends were studied. The results showed the PVC blends plasticized with PPC were with high thermal degradation stability, excellent flame retardant property and resistance to migration.2. DOPO groups containing castor oil based flame retardant plasticizer(PCOPE-1) was synthesized by epoxidation reaction, ring opening reaction and esterification from castor oil.Flame retardant PVC materials were prepared via blending with PCOPE-1. The results showed when all DOP was completely substituted with PCOPE-1 in PVC blends, limiting oxygen index(LOI) value increased from 23.6 % to 36.7 %, the Td, T50, Tp1 and Tp1 reached 289.4,318.2, 293.8 and 444.3℃, respectively. The peak of heat release rate(pHRR) value decreased from 379.04 kW/m2 to 262.29 kW/m2, the average heat release rate(av-HRR) decreased from162.32 kW/m2 to 108.42 kW/m2. Total heat release(THR) decreased from 31.78 MJ/m2 to17.9 MJ/m2. The results indicated that PCOPE-1 improved flame retardant property of PVC blends.To enhance the flame retardant performance of castor oil based flame retardant plasticizer,a flame retardant plasticizer based on castor oil derivatives(PCOPE-2) was synthesized.TGA-FTIR indicated that most of phosphorous-containing components such as metaphosphorous acid(HPO2) generated from thermal degradation of PCOPE-2, which retained in the condense phase rather than gaseous phase. These phosphorous-containing components promoted the carbonization of PVC blends to produce consolidated and compact carbon layer, which prevented mass and heat transferring between the gas and condensed phases and protected the underlying material from further combustion. The tensile strength(22.72 MPa) and elongation at break(350.82 %) of PVC materials plasticized only with PCOPE-2 manifested that PCOPE-2 modified the mechanical properties as the main plasticizer for PVC.3. A flame retardant chlorinated phosphate ester based on castor oil(CPECO) was synthesized. The application of CPECO and DOP as mixing plasticizer for PVC not only gained satisfied flame retardancy and mechanical properties, but also substituted for DOP partly. The results showed that LOI value of plasticized PVC blends increased from 23.6 % to35.4 %. TGA-FTIR and TGA-MS detected that the main pyrolysis products of PVC blends were H2 O, HCl, CO2, CO and C6H6. The glass-transition temperature(Tg), mechanical properties of PVC blends and migration stability of CPECO were investigated.4. To improve the flame retardant effect of castor oil based plasticizer in gas phase, a THEIC groups containing castor oil based flame retardant plasticizer(THEIC-MR-phosphate)was synthesized. PVC blends was palsticized with THEIC-MR-phosphate. The results showed that THEIC-MR-phosphate improved the thermal stability of PVC materials at around 300~600℃. When DOP was replaced with THEIC-MR-phosphate gradually in PVC materials,THEIC-MR-phosphate reduced the Tg and improved the flexibility of PVC materials. THR decreased gradually in the whole process. The time to reach peak of smoke production release(p-SPR) became longer. THEIC-MR-phosphate made a excellent smoke suppression effect in the cone tests. THR curves were similar to the total smoke release(TSR) curves, THR curves were all lagged behind the TSR curves, indicating that the combustion material was soot.5. DOPO groups containing castor oil based flame retardant reactvie plasticizer(EAMR-DOPO) was synthesized from castor oil. PVC materials modified with flame retardant plasticizer based on caster oil was successfully synthesized by “Click Chemistry”.The obtained flame retardant PVC polymeric materials based on castor oil presented relative molecular mass of 23 825 with dispersion index of 1.3. The thermal stability of the polymeric materials was excellent at high temperature. Tg decreased from 87.0℃ to 46.4℃ with more EAMR-DOPO reactived with PVC-N3.THEIC groups containing castor oil based flame retardant reactvie plasticizer was synthesized from castor oil(THEIC-MR-P). Then the flame retardant polymeric PVC material based on castor oil was synthesized by the “Click Chemistry” reaction of PVC-N3 and propargyl THEIC-MR-P. The obtained flame retardant PVC polymeric materials based on castor oil presented relative molecular mass of 24 087 with dispersion index of 1.3.The thermal stability of the polymeric materials was better at above 350℃ than PVC. Tg decreased from 87.0℃ to 51.4℃. The mehthod kept the property of PVC materials for a long time with zero migration.