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以去离子水为分散介质,聚乙烯醇(PVA)、羧甲基纤维素钠(CMC)、十二烷基苯磺酸钠(SDBS)为分散剂,采用沉降法、傅里叶变换红外光谱(FTIR)、Zeta电位、透射电镜(TEM)等测试表征手段研究了不同分散剂及含量对WC粉体在水介质中分散稳定性的影响,并探讨了相应分散机制。研究结果表明:聚乙烯醇、十二烷基苯磺酸钠和羧甲基纤维素纳均对WC悬浮液起到一定的分散作用,其中PVA和CMC的效果较好,当PVA和CMC的添加量分别为(质量分数)4.00%和0.30%时,24 h时的相对沉降高度分别为92.24%和91.29%。SDBS只能在短时间内提高WC粉体的分散稳定性,且对添加量敏感。3种分散剂的分散机制各不相同,PVA的分散作用主要为位阻分散机制,因此可长时间保持分散稳定性;SDBS以静电分散为主,过量的分散剂引起双电层压缩斥力减小,导致其分散稳定性对添加量敏感;而CMC则主要依靠电空间位阻分散机制,静电斥力和空间位阻的双重作用使得CMC在低添加量时就能达到长久高效的分散作用。
Using deionized water as dispersion medium, polyvinyl alcohol (PVA), sodium carboxymethylcellulose (CMC) and sodium dodecylbenzenesulfonate (SDBS) as dispersants, the sedimentation method, Fourier transform infrared spectroscopy (FTIR), Zeta potential and transmission electron microscopy (TEM) were used to study the influence of different dispersants and their contents on the dispersion stability of WC powders in aqueous media. The corresponding dispersion mechanism was also discussed. The results show that polyvinyl alcohol, sodium dodecyl benzene sulfonate and sodium carboxymethyl cellulose all play a role of dispersion of WC suspensions. PVA and CMC have good effect. When adding PVA and CMC The relative settlement height at 24 h (mass fraction) of 4.00% and 0.30% were 92.24% and 91.29%, respectively. SDBS can only improve the dispersion stability of WC powder in a short time and is sensitive to the amount of addition. The dispersion mechanism of the three dispersants varies. Dispersion of PVA is dominated by the steric dispersion mechanism, so the dispersion stability can be maintained for a long time. The dispersion of SDBS is dominated by electrostatic dispersion. The excessive dispersant causes the reduction of the repulsive repression of the electric double layer , Leading to its dispersion stability is sensitive to the amount of addition; and CMC mainly rely on electrical steric hysteresis dispersion mechanism, electrostatic repulsion and steric hindrance of the dual role of the CMC at low additions can achieve long-term and efficient dispersion.