Qianqian Shang

Internally plasticized PVC materials via covalent attachment of aminated tung oil methyl ester

We developed an internal plasticizer of aminated tung oil methyl ester for the production of non-migration, phthalate-free flexible and internally plasticized poly(vinyl chloride) (PVC) materials. The chemical structure of the synthesized aminated tung oil methyl ester and the internally plasticized PVC materials were characterized. The obtained internally plasticized PVC materials presented a lower glass transition temperature (Tg) and were more flexible than pure PVC. The thermal stability of internally plasticized PVC materials was less thermally stable compared to those of pure PVC due to the active secondary amine groups of aminated tung oil methyl ester. However, the modified PVC materials presented no migration for self-plasticizing PVC films but 15.7% weight loss for 50 wt% of the PVC/Dioctyl phthalate (DOP) system. It is expected that the PVC materials can be widely used in areas with high migration resistance requirements.

Synthesis and characterization of novel renewable castor oil-based UV-curable polyfunctional polyurethane acrylate

In recent years, a lot of interest has been given to renewable resources for their environmental friendliness and potential biodegradability in the synthesis of urethane-derived polymers. In this work, UV-curable castor oil-based polyfunctional polyurethane acrylate (COPUA) was prepared by the reaction of isophorone diisocyanate (IPDI) with castor oil and pentaerythritol triacrylate (PETA). The structures and molecular weights of the targeted IPDI–PETA and COPUA were characterized by FTIR, 1H NMR, and GPC, respectively. In addition, the effect of reactive diluent content on damping properties, thermal stabilities, and mechanical properties of COPUA was characterized by dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and universal test machine. DMA revealed the copolymers had a glass transition temperature (Tg) from 31.81 to 48.09°C. TGA showed that thermal initial decomposition temperatures were above 344.5°C, indicating the copolymers had certain thermal stability. Finally, some physical properties of curing films were studied by the contact angle and water absorption, and the results showed that the coatings exhibited good hydrophobicity. The COPUA obtained from castor oil can be used as eco-friendly materials and other applications alternative to the use of other petrochemicals in coatings.

Bio-inspired hydrophobic modification of cellulose nanocrystals with castor oil

This work presents an efficient and environmentally friendly approach to generate hydrophobic cellulose nanocrystals (CNC) using thiol-containing castor oil (CO-SH) as a renewable hydrophobe with the assist of bio-inspired dopamine at room temperature. The modification process included the formation of the polydopamine (PDA) buffer layer on CNC surfaces and the Michael addition reaction between the catechol moieties of PDA coating and thiol groups of CO-SH. The morphology, crystalline structure, surface chemistry, thermal stability and hydrophobicity of the modified CNC were charactered by TEM, XRD, FT-IR, solid-state 13C NMR, XPS, TGA and contact angle analysis. The modified CNC preserved cellulose crystallinity, displayed higher thermal stability than unmodified CNC, and was highly hydrophobic with a water contact angle of 95.6°. The simplicity and versatility of the surface modification strategy inspired by adhesive protein of mussel may promote rapid development of hydrophobic bio-based nanomaterials for various applications.

Bio-based reactive diluent derived from cardanol and its application in polyurethane acrylate (PUA) coatings with high performance

A UV-curable cardanol-based monomer (ECGE) was prepared using cardanol and epichlorohydrin, followed by epoxidation of the unsaturation in alkyl side chains of cardanol segments. After its chemical structure was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance (1H NMR), ECGE was used as a reactive diluent to copolymerize with castor oil-based polyurethane acrylate (PUA) and a series of UV-curable coatings were prepared. Results showed that the viscosity and volume shrinkage of the UV-curable PUA system decreased significantly after the introduction of cardanol-based monomer while maintaining reasonably high bio-renewable contents; when containing 50% of ECGE, the biomass content reaches 66.2%, which is 1.41 times that of pure resin. In addition, the coating properties were evaluated to determine hardness, adhesion, flexibility, and water resistance. The properties of UV-curable thermoset were also studied using tensile testing, dynamic mechanical thermal analysis, and thermogravimetric analysis. The cardanol-based coatings showed excellent adhesion, flexibility, medium hardness, and enhanced char yield although tensile strength, tensile modulus and glass transition temperatures were somewhat diminished. All these performances can be attributed to the unique architectures of ECGE that combined the structural features of rigid benzene ring and long flexible alkyl chains. The UV-curing behavior was determined using real-time IR, and the results indicated that the conversion of unsaturated bond was increased with more concentration of ECGE.

Mechanical property of lignin-modified phenolic foam enhanced by nano-SiO 2 via a novel method

Recently, the application of nano-SiO2 in composite materials has received wide attention. In this work, a new method was explored to prepare nano-SiO2 using phenol instead of other organic alcohols. The obtained nano-SiO2 was characterized by Fourier transform infrared spectroscopy (FT-IR) and by the zeta potential method. The phenol dispersant containing the prepared nano-SiO2 exhibited much higher reactivity toward formaldehyde than pure phenol. The preparation parameters of phenolic resin (PR) involved by nano-SiO2 were mild. This novel phenolic resin was successfully applied to fabricate a phenolic foam (PF) with a 153% increase in compressive strength.