Hongguang Dai

Three nontoxic carbohydrates (ribose, xylose, fructose) were used as poly(vinyl alcohol) (PVA) plasticizers to prepare PVA films using a casting method. Fourier transform infrared spectra demonstrated that hydrogen bonds formed between the carbohydrate and PVA. The crystallinity of raw PVA and PVA film plasticized by carbohydrate was characterized by X‐ray diffraction. Differential scanning calorimetry showed that carbohydrate decreased the melting point ( T _m ) of PVA. The decomposition temperature of PVA increased with addition of carbohydrate. The thermal stability of PVA film plasticized by carbohydrate (CAPF) was higher than that of PVA film plasticized by glycerol (GLPF). The thermal processing window of CAPF was broader than that of GLPF. The water vapor resistance of CAPF was better than that of GLPF. The mechanical properties of PVA films stored at different relative humidity were studied. Generally, the tensile strength of CAPF was larger than that of GLPF, while the elongation at break of CAPF was close to that of GLPF. Our experimental results indicate that carbohydrates are effective plasticizers for PVA. J. VINYL ADDIT. TECHNOL., 25:E181–E187, 2019. © 2018 Society of Plastics Engineers

N,N‐Bis(2‐hydroxyethyl)formamide, N‐(2‐hydroxyethyl)formamide (HF), N‐(2‐hydroxyethyl)‐N‐methylformamide, and N‐(2‐hydroxypropyl)formamide were used as poly(vinyl alcohol) (PVA) plasticizers to prepare PVA films by casting method. The four synthesized compounds were hydroxyalkylformamides (HAF). Fourier‐transform infrared spectra demonstrated that hydrogen bond interaction between the new plasticizers HAF and PVA occurred. The crystallinity of PVA and PVA film was characterized by X‐ray diffraction. Differential scanning calorimetry showed that HAF could decrease the melting point (T_m) of PVA. For PVA films with the same weight content plasticizer, the lower the molecular mass of plasticizer was, the lower the T_m of PVA was. The T_m of HF‐plasticized PVA was lower than that of traditional glycerol‐plasticized PVA. Generally, water‐vapor resistance of HAF‐plasticized PVA film was better than that of glycerol‐plasticized PVA film. The mechanical properties of PVA films stored at different relative humidity were studied. HAF were effective plasticizers for PVA. POLYM. ENG. SCI., 58:E145–E150, 2018. © 2017 Society of Plastics Engineers

N,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new additive to prepare thermoplastic starch/montmorillonite (TPS/MMT) nanocomposites. Here, BHF acted as both plasticizer for TPS and swelling agent for MMT. The hydrogen bond interaction among BHF, starch, and MMT was proven by Fourier transform infrared (FTIR) spectroscopy. By scanning electron microscope (SEM), starch granules were completely disrupted. Atomic force microscopy demonstrated that partially exfoliated TPS/MMT nanocomposites were formed. The crystallinity of corn starch, MMT, BHF‐plasticized TPS (BTPS), and TPS/MMT nanocomposites was characterized by X‐ray diffraction (XRD), XRD demonstrated that partially intercalated TPS/MMT nanocomposites were formed. The water resistance of TPS/MMT nanocomposites increased compared with that of pure BTPS. Mechanical properties of BTPS and TPS/MMT nanocomposites were examined. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers

The crystallinity of hydroxyalkylformamides‐platicized thermoplastic starch (HAFTPS) was characterized by X‐ray diffraction (XRD). The HAFTPS crystallinity related to the structure of plasticizer hydroxyalkylformamides (HAF). If there was one H atom attaching to N atom of HAF, the corresponding HAFTPS only had VA crystallinity; if there was no H atom attaching to N atom of HAF, the corresponding HAFTPS had EH crystallinity due to the bulky plasticizer.

N,N ‐bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for pea starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and pea starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscope (SEM), pea starch granules were completely disrupted, and the homogeneous materials were obtained. The crystallinity of pea starch and BHF‐plasticized thermoplastic pea starch (BTPS) was characterized by X‐ray diffraction (XRD). Rheological properties of TPS were analyzed. The water resistance of BTPS was better than that of glycerol‐plasticized thermoplastic pea starch (GTPS). At RH 33%, the tensile strength of BTPS was higher than that of GTPS for TPS containing 30% plasticizer. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

To prepare curcumin nanoparticles and evaluate the in vitro release of curcumin. The chitosan-graft-vinyl acetate copolymers were synthesized by free radical polymerization. Curcumin nanoparticles were synthesized by ultrasonic irradiation. The encapsulation efficiency of the nanoparticles and the in vitro release of curcumin were studied. The nanoparticles were discrete and uniform spheres, covered with positive charges. The encapsulation efficiency of nanoparticles was up to 91.6%. The in vitro release profile showed the slower release rate of curcumin. The methods is simple. The nanoparticles possess good physical performance and sustained release character in vitro.

N,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new plasticizer for corn starch to prepare thermoplastic starch (TPS). The hydrogen bond interaction between BHF and starch was proven by Fourier‐transform infrared (FT‐IR) spectroscopy. As detected by scanning electron microscopy (SEM), starch granules were completely disrupted and a continuous phase was obtained. The crystallinity of corn starch and BHF‐plasticized TPS (BTPS) was characterized by X‐ray diffraction (XRD). The thermal behavior of glycerol‐plasticized TPS (GTPS) and BTPS was investigated by differential scanning calorimetry (DSC). The water resistance of BTPS was better than that of GTPS. Generally, at low relative humidity (RH), the tensile strength of BTPS was higher than that of GTPS. At high RH, the elongation at break of BTPS was higher than that of GTPS.