Starch-g-poly (vinyl alcohol) as Compatibilizer for Reducing the Phase Separation Rates of Polyvinyl Alcohol/Cornstarch Pastes

Starch- g-poly(vinyl alcohol) as a compatibilizing agent for reducing the phase separation rates of polyvinyl alcohol/starch pastes has been investigated by blending and dissolving the two polymers in distilled water. The separation rates were quantitatively evaluated by the term of initiul demixing time. The grafted starches, with a series of grafting ratios, were prepared by grafting a number of vinyl acetate onto granular cornstarch in aqueous dispersion and then alcoholating in methanol. It was found that the addition of small amounts of starch- g poly (vinyl alcohol ) in the size compositions can effectively decrease the separation rates of the blended pastes in comparison to pure starch/PVA ones.Moreover, the influence of the grafting ratio, starch content, and PVA variety on the separation rates was also studied.

淀粉粘度对淀粉/PVA混合浆相分离行为的影响

通过控制淀粉酸解时间以制取不同粘度的淀粉试样 ,并以混合浆液的初显分离时间、相分离百分率和沉降率为量化指标 ,研究了淀粉粘度对淀粉 / PVA混合浆液相分离行为的影响 .实验结果表明 ,淀粉的粘度值对其混合浆液的相分离行为有显著影响 .随着淀粉粘度的降低 ,混合浆液的初始相分离速度减小 ,但中后期相分离速度提高 ,沉降率增大 .此外 ,还在不同淀粉粘度条件下 ,研究了混合浆组分及

氨基甲酸酯化变性对淀粉/PVA混合浆相分离的影响

以初显分离时间和沉降率为量化指标,定量研究并评估了淀粉氨基甲酸酯化变性对淀粉/PVA混合浆液相分离行为的影响.淀粉氨基甲酸酯是由工业玉米原淀粉与尿素经固相反应制成.实验结果表明,氨基甲酸酯化变性对淀粉/PVA混合浆液的相分离行为有显著影响,它能延长混合浆液的初显分离时间,降低相分离速度,提高混合浆液的稳定性,减小淀粉与部分醇解PVA混合浆液的相分离程度,但却使淀粉/PVA -1799混合浆液的沉降率有所增大.提高氨基甲酸酯化的变性程度,混合浆液的相分离程度降低,但对初始相分离速度的影响不大.此外,本文也分析了淀粉/PVA混合浆液的相分离机理。

低取代度阳离子淀粉与PVA混合浆液的相分离行为研究

通过改变 3-氯 - 2 -羟丙基三甲基氯化铵的用量 ,制备了一系列具有不同变性深度的低取代度季铵型阳离子淀粉 ;然后以初显分离时间和沉降率为量化指标 ,定量研究了低取代度阳离子淀粉的变性深度、混合比例及 PVA分子结构对淀粉与 PVA混合浆液的相分离行为的影响。结果发现 ,阳离子淀粉的取代度及混合比例都对该混合浆液的相分离行为影响很大 ,而

淀粉品种对淀粉与PVA混合浆相分离行为的影响

以初显分离时间和沉降率为量化指标 ,选择木薯、玉米及小麦三种原淀粉 ,定量研究了淀粉品种对淀粉与PVA 1 799及PVA 1 788混合浆的相分离行为的影响。实验结果表明 :淀粉品种和混合比例对混合浆液的相分离行为有显著影响 ,而PVA醇解度的影响则相对较小 ;按小麦淀粉、玉米淀粉、木薯淀粉的顺序 ,混合浆相分离速度逐渐降低 ;随着混合浆中淀粉含量的改变 ,其相分离速度呈“U”形变化特性 ,变化趋势随小麦淀粉、玉米淀粉、木薯淀粉这一顺序加强。

变性和增塑剂对淀粉/PVA混合浆相分离速度的影响

以初显相分离时间为指标,评价磺基-2-羟丙基变性和癸二酸交联变性对淀粉/PVA混合浆相分离速度的影响,考察增塑剂品种及用量,以及淀粉共混比例对磺基-2-羟丙基木薯淀粉(HPSS)和癸二酸交联木薯淀粉(SACLS)分别与PVA所成混合浆相分离速度的影响。结果表明:2种变性明显降低了淀粉/PVA-1799混合浆的相分离速度,3种增塑剂均能降低HPSS/PVA-1799、SACLS/PVA-1799混合浆的相分离速度,且丙三醇的作用效果最好。丙三醇用量分别为6%和10%时,2种混合浆展示最低相分离速度。随着共混比例的增加,相分离速度先加快后减缓。

Study On the Method for Evaluating the Compatibility of Polyvinyl Alcohol-starch Pastes

A revising method for evaluating the separation behavior of polyvinyl alcohol - starch pastes used as warp sizes had been studied and developed. Cosolvent method involves two important indexes for appraising the separation behavior: (l) initial demising time, and (2) subsidence ratio. However, they sometimes gave confused results because of the different measuring conditions. For obtaining the indexes accurately, the measuring parameters such as paste concentration, component content, and subsidence period of time were carefully studied and proposed. Besides accuracy, the proposed condition could give larger measuring scope and higher sensitiveness than the old one. Moreover, the influences of the paste concentration, component content, and molecular structure of polyvinyl alcohol upon the separation were also investigated. The experiments indicated that the paste concentration and starch content had much effect on the phase separation, whereas the influence of the molecular structure of polyvinyl

干法变性温度对淀粉糊化及混合浆相分离的影响

通过比较不同温度处理过的淀粉试样与原淀粉的Brabender粘度曲线 ,探讨了变性淀粉浆料干法生产过程中反应温度与淀粉糊化特性之间的联系。然后以初显分离时间和沉降率为量化指标 ,定量评估了该温度对淀粉与PVA 1799及PVA 1788混合浆液相分离的影响。实验结果表明 ,提高变性淀粉浆料干法生产过程中的反应温度 ,有助于降低淀粉的糊化温度和浆液粘度 。

聚丙烯酸酯浆料的酯基对混合浆相分离的影响

以初显分离时间和沉降率为量化指标,研究了酯基类型和含量、PVA类型、淀粉含量对混合浆相分离的影响.实验结果表明:酯基类型及数量对淀粉 /PVA混合浆液的相分离行为有明显影响,BA链节有利于混合浆液的稳定性,而MA和MMA则能获取相对较低的相分离程度.随着BA含量的增加,混合浆的相分离速度减小,但相分离程度却有所增大.所介绍的几种聚丙烯酸酯浆料有助于降低淀粉与部分醇解型PVA混合浆液的相分离速度,不能改善淀粉与完全醇解型PVA混合浆的相分离速度.

湖北省南漳县红星磷矿磷块岩特征与物质组分研究

湖北省南漳县震旦系沉积型红星磷矿矿体P_2O_5平均含量23.91%,矿石自然类型主要为角砾状磷块岩,其次为白云质磷块岩、泥质纹层状和条带状致密块状磷块岩。工业类型主要为钙(镁)质和硅钙(镁)质磷矿,其次为硅质磷矿。矿石矿物为胶状磷灰石和微晶磷灰石,经x-射线衍射物相分析,其种属为含碳氟磷灰石。嵌布粒度以细-中粒为主。脉石矿物主要为白云石、伊利石、高岭石、铁质。经测定当磷块岩磨矿粒度小于0.1mm,其磷酸盐矿物单体解离率可达92.53％,这为确定合理的选矿流程具有实际意义。