Mesocarbon microbeads (MCMB) were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440℃ for lh. By investigating the morpholog...Mesocarbon microbeads (MCMB) were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440℃ for lh. By investigating the morphology of mesophase spheres and the structure of the MCMB carbonized at 1000℃ for lh using scanning electron microscope (SEM) and XRD, it was found that phenolic resin accelerated the formation and coalescence of mesophase spheres. Some of the obtained MCMB were hi- or tri-spheres with the distorted microtextural carbon layers. Hexamethylenetetramine in the pitch modified by phenolic resin accelerated the condensation of phenolic resin and consequently expedited the combination of mesophase spheres, which was proved by the formation of some tetra-spheres. Owing to the cross-linkage of the additives, MCMB with complex structure were obtained.展开更多
A novel thermosetting resin system for superabrasives based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and then copolymerized with BMI. The structure of allyl novolak and reacti...A novel thermosetting resin system for superabrasives based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and then copolymerized with BMI. The structure of allyl novolak and reaction mechanism were analyzed by FFIR. Thermal and mechanical properties were characterized by using com- prehensive thermal analyzer (DSC-TG) and strength tester, respectively. The results showed that high molecular weight of novolak was advantageous for heat-resistance, but was unfavorable for the bending strength. High allyl content improved the heat-resistance but lowered the bending strength. When the molecular weight of novolak was 450 and allyl content was 50%, the best resin system with good heat-resistance and bending strength was obtained. It was suitable for the manufacturing of superabrasive tools.展开更多
Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve...Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane (PU) coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.展开更多
Three polymeric adsorbents with hydrogen bonding acceptors, methylamine, N-methyl-acetamide and aminotri(hydroxymethyl)methane modified resins are synthesized from chloromethylated X-5 resin. Adsorption isotherms of p...Three polymeric adsorbents with hydrogen bonding acceptors, methylamine, N-methyl-acetamide and aminotri(hydroxymethyl)methane modified resins are synthesized from chloromethylated X-5 resin. Adsorption isotherms of phenol and theophylline onto the three modified resins and the original X-5 resin from aqueous solution are measured. The results show that adsorption of compounds with hydrogen bonding donor onto methylamine and N-methylacetamide modified resins is enhanced as compared with that onto X-5 resin, and adsorption mechanism between the adsorbents and the adsorbates is mainly based on hydrogen bonding and hydrophobic interaction. While adsorption of compounds with hydrogen bonding donor onto aminotri(hydroxymethyl)methane modified resin is lowered as compared with that onto X-5 resin, and adsorption mechanism between the adsorbent and the adsorbates is mainly based on hydrophobic interaction.展开更多
基金Supported by the National Natural Science Foundation of China (No.50172034).
文摘Mesocarbon microbeads (MCMB) were prepared from coal tar pitch modified by phenolic resin and from the same pitch modified by phenolic resin and hexamethylenetetramine at 440℃ for lh. By investigating the morphology of mesophase spheres and the structure of the MCMB carbonized at 1000℃ for lh using scanning electron microscope (SEM) and XRD, it was found that phenolic resin accelerated the formation and coalescence of mesophase spheres. Some of the obtained MCMB were hi- or tri-spheres with the distorted microtextural carbon layers. Hexamethylenetetramine in the pitch modified by phenolic resin accelerated the condensation of phenolic resin and consequently expedited the combination of mesophase spheres, which was proved by the formation of some tetra-spheres. Owing to the cross-linkage of the additives, MCMB with complex structure were obtained.
文摘A novel thermosetting resin system for superabrasives based on novolak and bismaleimide (BMI) was developed. The novolak resin was allylated and then copolymerized with BMI. The structure of allyl novolak and reaction mechanism were analyzed by FFIR. Thermal and mechanical properties were characterized by using com- prehensive thermal analyzer (DSC-TG) and strength tester, respectively. The results showed that high molecular weight of novolak was advantageous for heat-resistance, but was unfavorable for the bending strength. High allyl content improved the heat-resistance but lowered the bending strength. When the molecular weight of novolak was 450 and allyl content was 50%, the best resin system with good heat-resistance and bending strength was obtained. It was suitable for the manufacturing of superabrasive tools.
文摘Castor oil is used to synthesize phenolic resin modified polyol. Castor oil, phenolic resin were taken in the molar ratio 0.07:0.027 and diethylene glycol (DEG) was also taken in varying hydroxyl numbers to achieve chemical modification in the backbone of synthesized polyol. Physico-chemical properties like acid value, OH value and moisture content of the modified polyol were measured. The prepared phenolic resin blended polyol were reacted with 4, 4-methylene diisocyanate and 2, 4-toluene diisocyanate to formulate the two component polyurethane (PU) coatings. Prepared coating is used to study properties such as gel time, surface dry, tack free and hard surface drying times. It was found that phenolic resin and diethyleneglycol used in synthesizing castor oil based modified polyols show the significant changes in physico-chemical properties of synthesized polyols. The variation in physico-chemical properties of synthesized polyol provide the information for desirable curing of polyurethane systems.
基金The National Natural Science Foundation of China (No.: 29974015 and 20174017)
文摘Three polymeric adsorbents with hydrogen bonding acceptors, methylamine, N-methyl-acetamide and aminotri(hydroxymethyl)methane modified resins are synthesized from chloromethylated X-5 resin. Adsorption isotherms of phenol and theophylline onto the three modified resins and the original X-5 resin from aqueous solution are measured. The results show that adsorption of compounds with hydrogen bonding donor onto methylamine and N-methylacetamide modified resins is enhanced as compared with that onto X-5 resin, and adsorption mechanism between the adsorbents and the adsorbates is mainly based on hydrogen bonding and hydrophobic interaction. While adsorption of compounds with hydrogen bonding donor onto aminotri(hydroxymethyl)methane modified resin is lowered as compared with that onto X-5 resin, and adsorption mechanism between the adsorbent and the adsorbates is mainly based on hydrophobic interaction.