水解聚丙烯腈铵对MMH／粘土体系胶体性能的影响

研究了水解聚丙烯腈铵盐（ＮＰＡＮ）对粘土颗粒、ＭＭＨ胶体粒子和ＭＭＨ／粘土复合体粒子电泳淌度的影响，发现ＮＰＡＮ能极大地增加粘土颗粒的负电性，说明ＮＰＡＮ在粘土颗粒表面发生了吸附作用；ＮＰＡＮ不仅能够削弱ＭＭＨ胶粒的正电性能，浓度足够大时甚至使ＭＭＨ胶粒由荷正电变为荷负电；ＭＭＨ／粘土复合体粒子电泳淌度的变化则是由于ＮＰＡＮ在粘土颗粒和ＭＭＨ胶粒上的共同吸附引起的。本文还研究了ＮＰＡＮ对ＭＭＨ／粘土体系流变性能的影响，认为ＮＰＡＮ在ＭＭＨ胶粒和粘土颗粒上的强吸附作用拆散了ＭＭＨ／粘土体系的网架结构，导致体系ＡＶ和ＹＰ降低。ＮＰＡＮ虽然能增加粘土颗粒的负电性，但是ＭＭＨ对含ＮＰＡＮ的粘土体系的增稠作用随ＮＰＡＮ加量的增加而削弱，说明ＭＭＨ胶粒与粘土颗粒的相互作用不宜简单地看作静电相互作用。     

New fabricate of styrene-butadiene rubber/montmorillonite nanocomposites by anionic polymerization

Styrene-butadiene rubber/montmorillonite (SBR/MMT) nanocomposites were successfully synthesized by in situ living anionic polymerization with n-BuLi as initiator. The results from kinetics study and ¹H NMR indicated that the addition of organophilic montmorillonite (OMMT) did not changed the living copolymerization and the components of the copolymer on the whole when OMMT content was lower than 3 wt %. However, gel permeation chromatography showed that the introduction of OMMT resulted in small amount of high-molecular weight fraction of SBR in the composites, leading to an increase in the weight-average molecular weight and polydispersity index, but the unchangeableness of the number-average molecular weight. The result from transmission electron microscopy and X-ray diffraction revealed that a completely exfoliated structure existed in the nanocomposite with 25 wt % styrene and OMMT content from 1 to 4 wt %, and styrene played an important role in the expanding of OMMT layers. Moreover, the nanocomposites possessed higher glass-transition temperature, thermal stability, tensile strength and elongation at break than SBR when the OMMT content ranged from 2.5 to 4 wt %. A schema was proposed to illustrate the formation of the nanocomposite and the exfoliation structure with physical cross-linking between SBR chains and OMMT.     

蒙脱石纳米复合材料基质制备研究

简要介绍了湖南某地钙基膨润土矿的矿石物质组成及性质 ,通过试验研究 ,提出了湿法分级提纯工艺流程 ,获得了蒙脱石含量 >90 %的膨润土精矿 ,为制备无机纳米复合材料提供了高性能的基质材料。     

Dispersion and roles of montmorillonite on structural,flammability, thermal and mechanical behaviours of electron beam irradiated flame retarded nanocomposite

In this work, the effects of montmorillonite (MMT) dispersion and electron beam irradiation on intercalation and flammability-thermal behaviours of alumina trihydrate (ATH) added low density polyethylene and ethylene vinyl acetate (LDPE–EVA) blends were investigated. MMT and ATH added LDPE–EVA blends were compounded using Brabender mixer and compression moulded into sheets. The samples sheets were electron beam irradiated in the dosage range of 0 to 250 kGy. The dispersion and intercalation of nano-MMT in LDPE–EVA matrix were investigated through X-ray diffraction (XRD) analysis. The d-spacing measurements revealed that the addition of nano-MMT has effectively intercalated into polymer matrix and this has enhanced the compatibility of ATH particles and LDPE–EVA matrix. Limiting oxygen index test (LOI) revealed that the incorporation of MMT into ATH added LDPE–EVA blends as improved the flame retardancy up to 26.5 LOI%. Besides, the application of electron beam irradiation were also improved the flame retardancy of the blends by increasing the LOI% for about 2% compared to non-irradiated samples. The application of irradiation dosage up to 250 kGy has rapidly improved the thermal stability of blends by delaying decomposition temperature and also promoting formation of char. The increasing of MMT loading level and irradiation dosage has effectively enhanced tensile strength and Young’s modulus by intercalating polymer matrix into interlayer galleries of MMT particles. Beside, the formation of crosslinking networks in polymer matrix also could further enhance the tensile strength and Young’s modulus. The intercalation effect of MMT particles and formation of crosslinking networks in polymer matrix could improve the thermal and mechanical properties. Consequently, this study has demonstrated that addition of MMT and electron beam irradiation into ATH added LDPE–EVA blends could produce better flammability, thermal and physical properties of ATH added LDPE–EVA blends.     

Preparation and mechanical properties of polypropylene / montmorillonite nanocomposites - After grafted with hard/soft grafting agent

Using a plastograph-mixer by the twin-screw mixed method to obtain the standard shaped specimens of polymer-clay nanocomposites (PCN), to prepare polypropylene (PP) / montmorillonite (MMT) nanocomposites pellets, grafting with two kinds of different surfactant − maleic anhydride (MA) or thermoplastic polyolefin elastomers (TPO). The chemical structure and polymer morphology of these as-synthesized PCN specimens were characterized by wide-angle powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, we prepare these experimental specimens in order to probe into its mechanical properties. These tests used are: layer distance of PCN, tensile, impact, shore-hardness, wearing tests, and so on.In addition, use XRD to make the characterization analysis, compare it to scatter and layer-distance. It is found that increasing the MA into the MMT, layer-distance at 5 wt% increase from 2.09 nm to 3.94 nm; and increase the TPO into the MMT, layer-distance at 1 wt% increase to the 3.27 nm.For the mechanical property, it is found that these specimens graft the MA have the following results: in the shore hardness test, the MMT weight percentage 5 wt% has the best result, increased by 51.2%. In the wearing test, the MMT 3 wt% strengthens by 81.48%. In addition, the specimens that graft the TPO, in the tensile test, increased by 5.79% have the best result.     

Studies on mechanical properties of dispersing intercalated silane montmorillonite in low density polyethylene matrix

In order to understand and improve these soft and weak mechanical properties of Low Density Polyethylene (LDPE), we add a silane modifier (Nanocor I.31PS) Montmorillonite (MMT) as reinforcement material, inserted with two kinds of different surfactant (thermoplastic polyolefin elastomers (TPO) or Maleic Anhydride (MA)), the layer distance and hydrophobia are all best; to join the pieces of LDPE together, making it possess polarization. After that, we use a Plastograph-Mixer by the twin-screw mixed method to obtain standard shaped specimens of Polymer-Clay Nanocomposites (PCN) to prepare HDPE/MMT nanocomposite pellets. By adding the different weight percentages (1, 3, and 5 wt.%) of MMT, and 2:1 ratio of MA (or TPO) and MMT, the layer distance of MMT and mechanical property of nanocomposites were investigated.The chemical structure and polymer morphology of these as-synthesized PCN specimens were characterized by wide-angle powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, we prepare these experimental specimens in order to probe into its mechanical properties. These tests used are: layer distance of PCN, tensile, impact, shore-hardness, wearing tests, and so on.In addition, we use XRD to make the characterization analysis, compare it to scatter and layer-distance. It is found that when increasing the TPO into the MMT, layer-distance at 1 wt.% MMT increases from 2.11 nm to 3.14 nm.It is found that these specimens that graft the TPO have the following results: In the tensile test, the MMT weight percentage of 1 wt.% has the best result, increased by 3.08%. In the impact test, the MMT 3 wt.% strengthens by 11.53%. In the hardness test, the MMT 5 wt.% strengthens the effect by 2.60%. In the wearing tests, the MMT 5 wt.% strengthens the effect by 6.98%.In addition, the specimens that graft the MA have the following results: In the tensile test, the MMT 1 wt.% strengthens by 5.39%. In the impact test, the MMT 3 wt.% strengthens by 19.71%. In the hardness test, the MMT 5 wt.% strengthens by 10.85%. In the wearing tests, the MMT 5 wt.% strengthens the effect by 44.19%.     

聚丙烯/尼龙/纳米蒙脱土膨胀型阻燃材料的研究

用尼龙6(PA6)代替季戊四醇(PT)作为成炭剂组成的膨胀型阻燃聚丙烯(PP)有熔滴、阻燃效果差的缺点，加入纳米蒙脱土(nano-MMT)作为阻燃剂的协效剂后可克服以上缺点。研究结果表明：加入质量分数为4％的nano-MMT不仅克服了阻燃体系熔滴的缺点，还使材料的拉伸强度提高了44．3％；热重分析和燃烧测试表明，nano-MMT的加入提高了材料的热稳定性，使剩炭率增加了12％，从而提高了材料的阻燃性能；由扫描电镜(SEM)观察发现：nano-MMT的加入增强了材料的界面粘结力，提高了材料的韧性，起到了一定的增容作用。     

粘土矿物研究中的若干问题

在新认识水平的基础上,对粘土矿物X射线衍射定量分析、混层粘土矿物的混层比计算及蒙脱石向伊利石转化的模式进行了讨论。着重指出了:对粘土矿物X射线衍射峰积分强度的影响因素和如何提高X射线衍射定量分析的准确度,通过用Δ2θ和衍射峰位移估计混层比的方法,以及Mac Ewan微晶模式、基本粒子模式、分凝模式和两相固溶体模式来模拟蒙脱石向伊利石转化过程中的优缺点。