Jianling Xia

Preparation of biobased epoxies using tung oil fatty acid-derived C21 diacid and C22 triacid and study of epoxy properties

In this work, a 21-carbon dicarboxylic acid (C21DA) and a 22-carbon tricarboxylic acid (C22TA) were prepared by the Diels–Alder addition of tung oil fatty acids with acrylic acid and fumaric acid, respectively, and subsequently converted to the corresponding di- and triglycidyl esters. There were no solvents used in the addition and glycidylation reactions. The excess epichlorohydrin used in the latter reaction could be recovered and reused. Furthermore, for the first time, calcium oxide was introduced as a water scavenger in the glycidylation process to effectively avoid the side reactions. The chemical structures of the products were confirmed using 1H NMR, 13C NMR and ESI-MS analyses. The curing behaviors of the di- and triglycidyl esters were studied using differential scanning calorimetry. Flexural, impact and dynamic mechanical properties of the cured resins were also determined. A commercial bisphenol A epoxy DER 332 and an epoxidized soybean oil (ESO) were used as controls in the study. Results indicated that the obtained diglycidyl and triglycidyl esters had overall superior performance to that of ESO for epoxy applications. Particularly, the triglycidyl ester of the C22TA displayed comparable strength, modulus and glass transition temperature to that of DER332.

Mixed calcium and zinc salts of dicarboxylic acids derived from rosin and dipentene: preparation and thermal stabilization for PVC

Maleated dipentene (DPMA) and 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 analysis. The effects of the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers on the PVC thermal stability were studied. In comparison, two commercial products, calcium stearate (CaSt2) and zinc stearate (ZnSt2), and two homemade salts of a dimer fatty acid (C36DA), zinc salt (C36DA-Zn) and calcium salt (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. The results showed that PVC compounds stabilized by the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers displayed comparable modulus and glass transition temperatures but exhibited overall superior thermal stability compared with the CaSt2/ZnSt2 stabilized PVC.

Preparation and characterization of acorn starch/poly(lactic acid) composites modified with functionalized vegetable oil derivates

Composites of acorn starch (AS) and poly(1actic acid) (PLA) modified with dimer fatty acid (DFA) or dimer fatty acid polyamide (DFAPA) were produced by a hot-melt extrusion method. The effects of DFA and DFAPA contents on the mechanical, hydrophobic, thermal properties and melt fluidity of the composites were studied under an invariable AS-to-PLA mass ratio of 40/60. SEM and DMA research results show that the compatibility of AS/PLA composites are determined by the dosage of DFA or DFAPA. The hydrophobicity and melt fluidity of composites are improved with the addition of DFA and DFAPA. The glass transition temperatures of the composites are all reduced remarkably by additives DFA and DFAPA. However, DFA and DFAPA exert different effects on the mechanical properties of AS/PLA composites. In the DFAPA-modified system, the tensile and flexural strength first increase and then decrease with the increase of DFAPA dosage; the mechanical strength is maximized when the dosage of DFAPA is 2 wt% of total weight. In the DFA-modified system, the tensile and flexural strength decrease with the increase of DFA dosage.

Renewable Myrcene-based UV-curable Monomer and its Copolymers with Acrylated Epoxidized Soybean Oil: Design, Preparation, and Characterization

An innovative myrcene-based ultraviolet curable vinyl ester monomer was synthesized, and its molecular structure was analyzed with Fourier transform infrared spectroscopy and nuclear magnetic resonance (1HNMR and 13CNMR) analysis. A series of copolymers were also prepared by mixing the myrcene-derived monomer with another vinyl ester monomer, acrylated epoxidized soybean oil, under ultraviolet light. The curing process was monitored using Fourier transform infrared spectroscopy. Ultraviolet curing analysis showed that all the mixed systems had high curing rates and were fully cured within the first 30 seconds. When the weight ratio of myrcene-derived monomer to acrylated epoxidized soybean oil was 50/50, the ultimate double bond conversion reached 94.08%. Dynamic mechanical analysis showed that the storage modulus and glass transition temperature of the cured resins both increased with increasing content of myrcene vinyl ester monomer because the molecular structure of myrcene-derived vinyl ester monomer was more rigid and stronger than that of acrylated epoxidized soybean oil. Thermogravimetric analysis indicated that the main thermal initial decomposition temperatures were all above 360 °C, demonstrating that the copolymers had modest thermal stability.

Mixed calcium and zinc salts of N-(3-amino-benzoic acid)terpene-maleamic acid: preparation and its application as novel thermal stabilizer for poly(vinyl chloride)

Dipentene-maleic anhydride (DPMA) was prepared by the Diels–Alder addition of dipentene with maleic anhydride. DPMA was converted via ammonolysis with para-aminobenzoic acid (PABA) to form N-(3-amino-benzoic acid)terpene-maleamic acid (ABDPMA), which was then converted to zinc soap (ABDPMA-Zn) or calcium soap (ABDPMA-Ca). Their chemical structures were confirmed by FT-IR and ICP-AES. Thermal stabilizing effects of ABDPMA-Ca/ABDPMA-Zn were compared with ABTMA-Ca/ABTMA-Zn (ABTMA: N-(3-amino-benzoic acid)tung-maleamic acid), C36DA-Ca/C36DA-Zn (C36DA: dimer fatty acid), ZnMA/ZnO (MA: maleic acid), EFC/ZnSt2/ESBO (EFC: calcium salt of epoxidised fatty acid; ESBO: epoxidised soybean oil, and CaSt2/ZnSt2 (St: stearic acid). Thermal stabilities of poly(vinyl chloride) (PVC) compounds were determined using Congo Red test, discoloration test, ultraviolet-visible spectroscopy analysis and thermogravimetric analysis. Dynamic mechanical and tensile properties of the PVC compounds were also studied. Besides better plasticization performance, ABDPMA-Ca/ABDPMA-Zn improved the long thermal stability of PVC compared with ABTMA-Ca/ABTMA-Zn, C36DA-Ca/C36DA-Zn, and CaSt2/ZnSt2.

Design, preparation and characterization of novel toughened epoxy asphalt based on a vegetable oil derivative for bridge deck paving

The aim of this work was to prepare a series of novel toughened epoxy asphalt materials using a natural oil derivative as the main raw material for bridge deck paving. A polymerized fatty acid (PFA) epoxy curing agent was prepared from epoxy fatty acid methyl ester (EFAME) via catalytic ring-opening polymerization and hydrolyzation. Then the novel toughened epoxy asphalt materials with different weight ratios of PFA were prepared. Mechanical tests showed that the prepared toughened epoxy asphalt materials had excellent flexible tensile properties. Micro-morphological investigation showed that the asphalt was dispersed more evenly with the increased PFA content, indicating excellent compatibility between the PFA cured system and asphalt. Dynamic mechanical analysis results showed two phases in the cured compositing system, and the changing trend of Tg indicates the excellent compatibility between the PFA cured system and asphalt. Comprehensive properties comparison showed that all performance parameters of our prepared toughened curing system met the technical requirements for bridge deck paving. Curing behavior research showed that the Ea of the optimal toughened mixed epoxy asphalt curing system was lower and close to the value of the pure epoxy curing system without asphalt.

Study on the synthesis of bio-based epoxy curing agent derived from myrcene and castor oil and the properties of the cured products

Two novel bio-based epoxy curing agents derived from myrcene (MMY) and castor oil (CMMY) were prepared, respectively. Their chemical structures were confirmed by Fourier transform infrared spectrometry (FTIR) and 1H nuclear magnetic resonance (1HNMR). The two curing agents were used to cure a commercial epoxy resin (E-51). The MMY-cured epoxy resin had very poor toughness while the CMMY-cured epoxy resin had low strength, so the two curing agents were mixed at different weight ratios to form new curing agents for the E-51 epoxy resin. The tensile strength, impact strength, dynamic mechanical properties, thermal stability, micro-morphology of fracture surfaces and gel content of the cured epoxies were all investigated. The curing behaviors of the cured epoxies were studied by differential scanning calorimetry (DSC). Results show that the elongation at break is increased and the tensile strength and glass transition temperature are decreased with increasing weight ratio of CMMY, while the impact strength is increased gradually. The initial degradation temperatures of all the cured epoxy resins were above 367 °C. The gel contents of the epoxy resins cured with the mixed curing agents were above 87%. The activation energies for the systems with MMY and CMMY were 75.90 and 67.69 kJ mol−1, respectively.

Development and characterization of ricinoleic acid-based sulfhydryl thiol and ethyl cellulose blended membranes

Ethyl cellulose (EC) membranes can be combined with efficient plasticizers derived from renewable resources to form supramolecular systems. In this paper, a novel ricinoleic acid-based sulfhydryl triol (STRA) was first synthesized and used as a plasticizer for EC membranes. A supramolecular membrane of EC and STRA using van der Waals forces was designed. The morphology, hydrophilic performance, thermal stability, and mechanical properties of the composites were investigated. While pure EC is brittle, its membrane ductility and hydrophilic performance can be improved by integration with STRA. The highest tensile strength was found in EC/STRA (90/10) (8.37MPa). Impressively, the EC/STRA(60/40) and EC/STRA(50/50) elongation at break values were 17.4 and 20.2 times higher, respectively, than that of pure EC. This novel ricinoleic acid-based sulfhydryl triol can be used as a feedstock for hydrophobic EC membranes.

Effects of preparation methods of mixed calcium and zinc thermal stabilizers derived from dimer fatty acid and tung-oil based C22 triacid on properties of PVC

Abstract Calcium and zinc salts of dimer fatty acids (DFA-Ca and DFA-Zn) were synthesized using direct neutralization and metathesis technologies, respectively. The adduct of maleic anhydride and methyl eleostearate (MAME) was also converted to the corresponding zinc soap (C22TA-Zn) and calcium soap (C22TA-Ca) by the two different synthetic routes. Mixed Ca/Zn salts between DFA-Ca and DFA-Zn, and between C22TA-Zn and C22TA-Ca were used as thermal stabilizers for poly(vinyl chloride) (PVC). The PVC thermal stability was determined using Congo red test, discoloration test, torque rheological analysis and TGA. Dynamic mechanical properties were also tested. Results indicated that the DFA-Ca/DFA-Zn thermal stabilizer from direct neutralization technology was found to be superior to that of the metathesis product. The C22TA-Ca/C22TA-Zn thermal stabilizer from direct neutralization method had overall superior thermal stability, and displayed modulus and glass transition comparable to that of metathesis product. Direct neutralization method was more excellent and convenient than metathesis technology.

Plasticization and thermal behavior of hydroxyl and nitrogen rich group-containing tung-oil-based ester plasticizers for PVC

Hydroxyl and nitrogen rich group-containing tung-oil-based ester (GEHTMA-1, GEHTMA-2, GEHTMA-3 and GEHTMA-4) plasticizers were successfully synthesized from tung-maleic anhydride and utilized to plasticize poly(vinyl chloride) (PVC). In comparison to petroleum-based plasticizers (e.g. DOTP), the mechanical test shows that bio-based GEHTMA-3 displays better mechanical properties, which means that GEHTMA-3 could endow PVC resins with well-balanced properties of flexibility and strength. With the addition of GEHTMA-3 into DOTP, PVC/DOTP/GEHTMA-3 exhibits better mechanical properties, plasticization performance, migration resistance and thermal stability compared with the PVC/DOTP system. Above all, PVC/28DOTP/12GEHTMA-3 shows the highest tensile strength and elongation of 32.19 MPa and 345.20%, respectively. PVC/32DOTP/8GEHTMA-3 displays the best thermal stability. The superior performance is attributed to the molecular interaction of GEHTMA-3 and DOTP with PVC. The interaction originates from the simultaneous introduction of hydroxyl, epoxy, benzene ring, ester and nitrogen rich groups into GEHTMA-3 structures. Besides, GEHTMA-3 presented good miscibility with PVC resins, particularly when a mixture of DOTP and GEHTMA-3 was used. In addition, possible plasticization of the PVC/DOTP/GEHTMA-3 system was presented.