Synthesis And Acting Mechanisms Of Polyacid Based PVC Ca/Zn Compound Thermal Stabilizers Derived From Oil And Rosin

As the demand for environmental protection is becoming stronger and stronger, it is becoming investigative emphasis and hot spot to develop the environmental friendly, efficient and multi-purpose thermal stabilizers. The goal of this work is to develop efficient and green plastic additives by making full use of our abundant renewable resources, such as woody oil and rosin. This work had synthesized new functional bio-based polacids, their calcium soap and zinc soap. This work also studied the effects of reacting conditions on Ca/Zn compound heat stabilizers and developed several higher-value bio-based Ca/Zn composite thermal stabilizers, such as the rosin/oil-based liquid thermal stabilizer, solid polyacid based Ca/Zn compound heat stabilizers derived from rosin and oil, and bio-based “multi-effect" plastic additives. The relationship between the structures and properties were studied and discussed in detail in this work as well. This work offered theoretical basis and references for the efficient utilization of natural renewable resources and the sustainable progress of the industry of environmental plastic thermal stabilizer. The specific contents are the following six parts:1. Calcium and zinc salts of dimer fatty acids(DFA) were synthesized using one- and two-step technologies. Calcium and zinc salts of DFA prepared from direct one-step method are named DFA-Ca-1 and DFA-Zn-1, respectively. Calcium and zinc salts of DFA prepared from two-step method are named DFA-Ca-2 and DFA-Zn-2, respectively. The thermal stability of poly-(vinyl chloride)(PVC) samples was determined using Congo red test, discoloration test, and thermogravimetric analysis(TGA). Results indicated that DFA-Ca-1/ DFA-Zn-1 thermal stabilizer derived from direct one-step method had overall superior thermal stability comparable to the DFA-Ca-1/ DFA-Zn-1 thermal stabilizer synthesized by the two-step product.2. In this work, a rosin/oil-based dimer acid(RODA) was first prepared by addition polymeration using rosin and fatty acids as feedstock. Then RODA was converted into a environment-friendly liquid thermal stabilizer(RODA-LTS). The chemical structures were examined by UV-Vis and Fourier Transform infrared spectroscopies. Thermally stabilizing effects of the resulting RODA-LTS for PVC were compared with that of two commercial LTSs(JRH-LTS-Ca/JRH-LTS-Zn and M509-LTS-Ca/Zn). The thermal stability of the stabilized PVC samples was determined using dehydrochlorination test, thermogravimetric analysis(TGA), Congo red test, and torque rheological analysis. Results indicated that the activation energy of thermal decomposition Eks was found to be in the following order: RODA-LTS(120.6 kJ/mol) > JRH-LTS-Ca/JRH-LTS-Zn(118.2 kJ/mol) > M509-LTS-Ca/Zn(105.4 kJ/mol). The RODA-LTS stabilized PVC had a significantly higher thermal stability than both control samples, which was probably due to the introduction of the rigid rosin moiety to the stabilizer structure. Tensile and dynamic mechanical properties of the PVC compounds were also studied, and the results indicated PVC compounds stabilized with RODA-LTS and commercial LTSs displayed comparable mechanical property.3. An adduct of dipentene and maleic anhydride(DPMA) and an acrylopimaric acid(APA) were prepared by the Diels-Alder addition of dipentene with maleic anhydride and gum rosin with acrylic acid, respectively, and subsequently converted to the corresponding zinc salts(DPMA-Zn, APA-Zn) and calcium salts(DPMA-Ca, APA-Ca). Their chemical structures were confirmed by FT-IR and XRD analysis. Effects of the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers on PVC thermal stability were studied. In comparison, commercial calcium stearate(CaSt2) and zinc stearate(ZnSt2) and a homemade zinc salt of dimer fatty acid(C36DA-Zn) and a calcium salt of dimer fatty acid(C36DA-Ca) were also employed as controls in the study of PVC thermal stabilization. The thermal stability of PVC samples was determined using thermogravimetric analysis(TGA), Congo red test and discoloration test. Dynamic mechanical properties of the PVC compounds were also studied. Results indicated that PVC compounds stabilized by the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers displayed comparable mechanical property compared with the CaSt2/ZnSt2 stabilized PVC. The stabilizing effects of the four mixed Zn/Ca stabilizers followed the order of DPMA-Ca/DPMA-Zn > APA-Ca/APA-Zn≥ C36DA-Ca/C36DA-Zn > CaSt2/ZnSt2, suggesting that the salts of dicarboxylic acids had higher stabilizing effect than that of monocarboxylic acid(St). The higher thermal stability of the PVC sample achieved with use of DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn was due to the presences of fused-ring bridge-ring structures in the molecules of the thermal stabilizers and relatively higher metal ion contents. The results from this study demonstrate that rosin acid and dipentene can be potential feedstocks for PVC thermal stabilizers.4. The calcium and zinc salts of C21 diacid and C22 triacid derived from eleostearic acid were prepared successfully. In comparison, commercial calcium stearate(CaSt2) and zinc stearate(ZnSt2) were also employed as controls in the study of PVC thermal stabilization. Effects of the mixed calcium and zinc thermal stabilizers on PVC properties were studied using thermogravimetric analysis(TGA), Congo red test, discoloration test and DMA. Results indicated that the long-term thermal stability of the PVC samples containing the same weight stabilizer followed the order of C21-DA-Ca/C21-DA-Zn > C22-TA-Ca/C22-TA-Zn > CaSt2/ZnSt2. Because C22-TA-Ca/C22-TA-Zn stabilizers belonged to the zinc –enriched thermal stabilizer, it was easier to cause“zinc burning”. PVC compounds stabilized by the mixed C22-TA-Ca/C22-TA-Zn stabilizers displayed comparable worse initial color compared with the C21-DA-Ca/C21-DA-Zn and CaSt2/ZnSt2 stabilized PVC samples containing the same weight stabilizer. By adjusting mounts of various components in thermal stabilizer system, this paper found that PVC compounds stabilized with C21-DA-Ca/C21-DA-Zn and C22-TA-Ca/C22-TA-Zn displayed comparable initial color and long-term thermal stability compared with the CaSt2/ZnSt2 stabilized PVC samples containing the same calcium and zinc content. The calcium and zinc content of C21-DA-Ca/C21-DA-Zn and C22-TA-Ca/C22-TA-Zn were higher than CaSt2/ZnSt2. So C21-DA-Ca/C21-DA-Zn and C22-TA-Ca/C22-TA-Zn could offer comparable initial color and long-term thermal stability compared with the CaSt2/ZnSt2 stabilized PVC samples and could reduce the dosage of thermal stability.5. The effects of epoxidized soybean oil(ESO), D-sorbitol, and β- diketone on the initial dyeing property and thermal stability of PVC/DOTP/DFA-Ca-1/DFA-Zn-1 system were also studied using Congo Red test and discoloration test. Epoxidized soybean oil, D-sorbitol, and β-diketone had significant synergistic effects on the long-term heat stability of PVC samples stabilized with DFA-Ca/DFA-Zn thermal stabilizers. It was worth noting that the initial color of PVC samples with β-diketone was lighter. The optimum formula for the DFA-Ca-1/DFA-Zn-1 composite stabilizer was 1.08 m(DFA-Ca-1) : 0.27 m(DFA-Zn-1) : 1 m(ESO) : 0.5 m(D-sorbitol) : 0.3 m(β-diketone). Adding 3.15 g of the optimum formula of DFA-Ca-1/DFA-Zn-1 composite stabilizers to 45 g of PVC/22.5 g DOTP gave static thermal stability time of up to 3 h 16 min 56 s at 185 ℃ with excellent initial color. That optimum formula also apply to the C21DA-Ca-1/ C21DA-Zn-1 stabilizers, which were the calcium and zinc salts of C21-DA prepared from direct one-step method.6. Calcium and zinc salt of polymerized fatty acid were prepared with natural unsaturated oil as raw material first, then the multi-function Ca-Zn composite thermal stabilizer(OMFCTS)was prepared by compounding calcium and zinc salts of polymerized fatty acid with antioxidants and β-diketone. Its structure was confirmed by Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES) and FT-IR. The thermal stability and mechanical properties of poly(vinyl chloride)(PVC) upon doping OMFCTS were determined by means of the tensile test, dynamic mechanical thermal analysis(DMA), torque rheometer,congo-red test and heat aging test methods. The results showed that the mechanical property and thermostability of the system 100 g PVC/ 30gDOP/3g OMFCTS can be comparable to the system 100 g PVC/40gDOP/3g commercially available Ca-Zn composite thermal stabilizer. OMFCTS could make PVC products better thermal stability as it simultaneously provide extra plasticization. OMFCTS can reduce the dosage of plasticizer.