With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration,...With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration, initiator concentration, matrix concentration, and reaction temperature on the percentage of grafting (G) and grafting efficiency (G_E) were studied. The results show that G and G_E values both increase with the the increase of EA concentration and KPS concentration; when raising HPMC concentration from 0.12 mmol/L to 0.47 mmol/L, G decreases, while G_E increases;and when raising reaction temperature from 50 ℃ to 65 ℃,G increases, but G_E decreases. In addition, the graft copolymers were characterized by Fourier transform infrared (FTIR) spectra and transmission electron microscopy (TEM) methods.展开更多
The effect of application of cellulose-based edible coating, hydroxypropyl methylcellulose (HPMC) to mature-green tomatoes on the firmness and color was investigated. Tomatoes were stored at 20℃ for up to 18 days. Fi...The effect of application of cellulose-based edible coating, hydroxypropyl methylcellulose (HPMC) to mature-green tomatoes on the firmness and color was investigated. Tomatoes were stored at 20℃ for up to 18 days. Firmness decreased as storage time increased in all treatments. However, application of HPMC edible coating delayed softening of tomatoes during 18 days of storage at 20℃ . At days 7, 13 and 18,the firmness of tomatoes coated with HPMC was significantly ( P ≤ 0.05) greater than the firmness of uncoated tomatoes. The study also confirmed that HPMC coatings could significantly (P≤0.05) delay the changes in color of tomatoes stored at 20℃ . The ripening of tomatoes from the pink stage to the red stage was successfully retarded. HPMC coating could extend the shelf life of fresh tomatoes. The retardation of the rate of loss of firmness could reduce the economic loss that would result from spoilage by mechanical injury during transportation of tomatoes.展开更多
Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepar...Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepare smart concrete aggregate with a mosaic structure(SAMS).The hydroxpropyl methylcellulose(HPMC)was taken into consideration to improve the properties of mortar;by using HPMC,the structure of SAMS was optimized and its mechanical and electrical properties were evaluated.The experimental results show that the toughness of mortar could be improved by the complex that formed by epoxy resin,and the effect of HPMC on the flexibility of CFc was greater than that on the flexibility of CFrc;the feasible designing indicates that the CFc-Z core and CFrc-Z core could be used as inner and outer cores of SAMS.When the proposed dosages of HPMC in inner and outer cores are 0.35wt%and 0.2wt%,respectively,it could give an effective prediction for the damage of concrete during the loading process.展开更多
文摘With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration, initiator concentration, matrix concentration, and reaction temperature on the percentage of grafting (G) and grafting efficiency (G_E) were studied. The results show that G and G_E values both increase with the the increase of EA concentration and KPS concentration; when raising HPMC concentration from 0.12 mmol/L to 0.47 mmol/L, G decreases, while G_E increases;and when raising reaction temperature from 50 ℃ to 65 ℃,G increases, but G_E decreases. In addition, the graft copolymers were characterized by Fourier transform infrared (FTIR) spectra and transmission electron microscopy (TEM) methods.
文摘The effect of application of cellulose-based edible coating, hydroxypropyl methylcellulose (HPMC) to mature-green tomatoes on the firmness and color was investigated. Tomatoes were stored at 20℃ for up to 18 days. Firmness decreased as storage time increased in all treatments. However, application of HPMC edible coating delayed softening of tomatoes during 18 days of storage at 20℃ . At days 7, 13 and 18,the firmness of tomatoes coated with HPMC was significantly ( P ≤ 0.05) greater than the firmness of uncoated tomatoes. The study also confirmed that HPMC coatings could significantly (P≤0.05) delay the changes in color of tomatoes stored at 20℃ . The ripening of tomatoes from the pink stage to the red stage was successfully retarded. HPMC coating could extend the shelf life of fresh tomatoes. The retardation of the rate of loss of firmness could reduce the economic loss that would result from spoilage by mechanical injury during transportation of tomatoes.
基金Funded by the Natural Science Foundation of Fujian Province(No.2016J01241)the National Natural Science Foundation of China(No.51608212)。
文摘Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepare smart concrete aggregate with a mosaic structure(SAMS).The hydroxpropyl methylcellulose(HPMC)was taken into consideration to improve the properties of mortar;by using HPMC,the structure of SAMS was optimized and its mechanical and electrical properties were evaluated.The experimental results show that the toughness of mortar could be improved by the complex that formed by epoxy resin,and the effect of HPMC on the flexibility of CFc was greater than that on the flexibility of CFrc;the feasible designing indicates that the CFc-Z core and CFrc-Z core could be used as inner and outer cores of SAMS.When the proposed dosages of HPMC in inner and outer cores are 0.35wt%and 0.2wt%,respectively,it could give an effective prediction for the damage of concrete during the loading process.
