Curing mechanism of alkaline phenolic resin with organic ester

来源 :China Foundry | 被引量 : 0次 | 上传用户:czn2000
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
To study the curing mechanism of alkaline phenolic resin with organic ester, three esters were chosen to react with three systems — alkaline phenolic resin, potassium hydroxide aqueous solution containing phenol, and potassium hydroxide aqueous solution. The variations of pH, heat release and gel pH during the reactions were monitored and measured. Infrared spectroscopy(IR) and thermal gravity analysis(TG) techniques were used to characterize the curing reaction. It was found that organic ester is only partially hydrolyzed and resin can be cured through organic ester hydrolysis process as well as the reaction with redundant organic ester. The sequential curing mechanism of alkaline phenolic resin cured by organic ester was identified as follows: a portion of organic ester is firstly hydrolyzed owing to the effect of the strong alkaline; the gel is then formed after the pH decreases to about 10.8-10.88, meanwhile, the redundant organic ester(i.e. non-hydrolysis ester) starts the curing reaction with the resin. It has also been found that the curing rate depends on the hydrolysis velocity of organic ester. The faster the hydrolysis speed of the ester, the faster the curing rate of the resin. To study the curing mechanism of alkaline phenolic resin with organic ester, three esters were chosen to react with three systems - alkaline phenolic resin, potassium hydroxide aqueous solution containing phenol, and potassium hydroxide aqueous solution. The variations of pH, heat release and gel pH During the reactions were monitored and measured. Infrared spectroscopy (IR) and thermal gravity analysis (TG) techniques were used to characterize the curing reaction. It was found that organic ester is only only hydrolyzed and resin can be cured through organic ester hydrolysis process as well as the reaction with redundant organic ester. The sequential curing mechanism of alkaline phenolic resin cured by organic ester was identified as follows: a portion of organic ester is now hydrolyzed due to the effect of the strong alkaline; the gel is then formed after the The mean decreases, the redundant organic ester (ie non-hydrolysis ester) starts the curin g has reaction with the resin. It has also been found that the curing rate depends on the hydrolysis velocity of organic ester. The faster the hydrolysis speed of the ester, the faster the curing rate of the resin.
其他文献
Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude ab
Micro milling has many advantages in fabricating three-dimensional(3D) structure in micrometer scale. The micro milling machine tool with high positioning accur
The synthesis of a low cost no-bake furan resin with a high strength was researched in this paper. Through the analysis of main factors influencing the strength
A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a
The effect of Si addition and heat treatment on the Al-5wt.%Fe alloy has been investigated by OM, SEM-EDS and XRD. The results show that the Si plays a signific
Crusher hammers for the mineral processing industry must meet the demands of both high wear resistance at the hammer head and high impact toughness at the hamme
The influence of Sr addition on pore formation in directionally solidified Al-12.3wt.% alloy was investigated using X-ray detection, optical microscope, and SEM
Sn60Pb40 alloy powders were fabricated using the planar flow casting(PFC) atomization process. By using OM, SEM and EPMA, the characteristics of the morphologie
To remove the inclusions in the ingots by conventional electroslag remelting (ESR), the bearing steel was prepared using ESR process but with mold rotation in t