表面活性剂对压敏胶在办公废纸再生过程中的影响

为了分析废纸中的胶黏物,采用胶黏物染色的方法对标签纸中胶黏物进行染色,使之与白色浆料形成色差对比,从而有助于用扫描法分析胶黏物的存在形式。论文系统地探讨了阳离子、阴离子、非离子表面活性剂对压敏胶胶黏物的作用以及对废纸浆的影响。对筛选前后纸片的胶粒尘埃度(NPM)和平均胶粒粒径的分析结果表明:阳离子、阴离子表面活性剂对胶粒有一定的分散作用,阳离子表面活性剂的分散作用尤为突出,而非离子表面活性剂有略微的凝聚作用。处理后纸浆滤液的浊度和胶黏物的接触角的变化规律也证实了以上结论。研究结果可为废纸脱墨过程中表面活性剂对脱墨纸浆中胶黏物的影响规律提供理论依据。     

改性滑石粉对防化肥结块效果的影响

研究硬脂酸、铝酸酯、钛酸酯对滑石粉的改性效果,以活化指数和接触角作为表征指标,得到滑石粉的较好的改性工艺参数:硬脂酸、钛酸酯、铝酸酯的用量分别为3%、2.5%、3%,改性时间为1.5 h,改性温度为65 ℃.分别利用粒度分析和扫描电镜观察改性前后滑石粉的粒度和形貌,发现改性滑石粉粒径减小,分散性提高.放置42 d后,未添加滑石粉的尿素和复合肥的结块率分别为26.79%和12.96%,结块强度分别为868.38 N/kg和1974.11 N/kg;添加3%钛酸酯改性的滑石粉作为防结块剂时,尿素和复合肥的结块率分别0.59%和0.46%,结块强度分别为30 N/kg和40 N/kg.     

环氧氯丙烷改性淀粉基胶黏剂的制备及性能研究

以玉米淀粉为原料,经双氧水氧化、环氧氯丙烷交联改性后以碱糊化制得环氧氯丙烷改性淀粉基胶黏剂。通过单因素实验及正交设计实验优化了环氧氯丙烷交联改性的实验条件。最佳工艺条件为:环氧氯丙烷用量为2%(相对于淀粉的质量分数)、反应温度为50℃、反应时间为4 h、交联反应体系的pH值为11。制备的胶黏剂的胶合强度可达4.4 kg/m~2,耐水时间为10 h,交联度为1.2。环氧氯丙烷交联改性淀粉基胶黏剂的性能明显优于氧化淀粉胶黏剂。     

TDI改性TiO2的制备及其对PU胶黏剂性能的影响

采用2,4-甲苯二异氰酸酯(TDI)对纳米TiO_2进行改性,然后将TiO_2和改性TiO_2分别加入聚氨酯(PU)胶黏剂中制备了单组分聚氨酯胶黏剂PUA和PUB。结果表明,TDI通过化学键键合在纳米TiO_2表面,改性TiO_2具有较强的吸收紫外线和可见光的能力。当改性TiO_2质量分数为0. 4%时,胶黏剂的拉伸剪切强度提高了约80%;经氙灯人工加速老化1 000 h后,PUB胶黏剂表面裂纹较少,羰基指数(CI)约为12;而纯PU表面裂纹宽且大,羰基指数约为45,添加改性TiO_2有效提高了材料的抗光氧老化性能。     

PE塑料胶黏剂的研制

以甲苯为溶剂,过氧化二苯甲酰(BPO)为引发剂,通过自由基聚合,采用丙烯酸(AA)接枝改性氯化聚丙烯(CPP),得到一种PE胶黏剂。研究了反应温度、反应时间、AA和BPO的质量对CPP胶黏剂改性的黏附性能的影响;得出较佳的工艺条件为:反应温度T=90℃,反应时间t=3h,反应物料的质量比m(CPP):m(AA):m(BPO)=100:3.0:0.5时,改性的CPP胶黏剂有较高的黏接强度。     

茭白废弃生物质苯酚液化及其产物树脂化制备胶黏剂

采用正交试验,考察了苯酚用量、催化剂用量、反应时间及反应温度对茭白废弃生物质液化效果的影响,并研究了该液化产物制备胶黏剂的影响因素。结果表明:茭白废弃生物质液化过程中,苯酚用量的影响最大,反应温度和反应时间次之,而催化剂用量的影响相对较弱,优化参数是苯酚用量为1∶5,催化剂用量为7%,反应时间为90 min,反应温度为140℃,在此优化条件下,液化率为95.83%。胶黏剂制备过程中,茭白液化物与甲醛的质量比为1∶1.8,高温缩聚反应温度为92℃较为合适。     

漆酶改善分离木素和OCC纸浆特性的研究

应用漆酶处理纤维素酶分离酶解木素和OCC(Old corrugated containers)纸浆,结果表明:木素在漆酶处理过程中会发生降解,经漆酶处理后再经加热处理会使木素发生聚合,木素降解主要发生在高分子量木素部分,而聚合作用主要发生在低分子量木素之间;木素经漆酶处理后,酚羟基的含量略有增加,这是由于在漆酶处理木素的过程中,木素不但发生酚氧自由基的离域现象,而且还有高分子量的木素发生降解产生了新的酚羟基;经不同用量的漆酶处理的OCC纸浆手抄片的湿环压指数和湿抗指数与对照样相比均有明显提高,特别是漆酶用量为24 U/g时,湿环压指数达到4.1 N.m/g,提高了41%。经不同用量的漆酶处理的OCC纸浆干环压强度和干抗张强度与对照样相比略有提高,但提高的幅度不大。     

原位聚合改性滑石粉/PP复合材料的微观结构和力学性能

通过熔融共混制备了丙烯酸丁酯(BA)原位聚合改性滑石粉/聚丙烯(PP)复合材料。研究了原位聚合改性对滑石粉/PP复合材料形貌、晶型结构、结晶熔融行为和力学性能的影响。结果表明,PP和滑石粉在熔融共混过程中,剪切力的作用使层叠的滑石粉剥离成不同厚度的片层,BA原位聚合改性改善了滑石粉与PP之间的界面粘结,有利于滑石粉在PP基体中的剥离;滑石粉的原位聚合改性,促进了β-晶型PP的生成,提高了滑石粉/PP复合材料中PP相的熔点、结晶速率和结晶度,降低了PP相的结晶温度。同时显著提高了滑石粉/PP复合材料的冲击强度,且存在一最佳的BA用量。     

KH-550改性纳米SiO2对环氧胶黏剂性能的影响

制备了氨基硅烷偶联剂（KH-550）表面接枝改性纳米SiO2粒子,利用正交实验,讨论了改性剂用量、改性温度以及改性时间对活化指数的影响。并将KH-550硅烷偶联剂包覆纳米SiO2作为填料,以环氧树脂E-44为基体,制备环氧树脂胶黏剂,通过对胶黏剂进行剪切强度,扫描电镜和阻抗测试,研究了改性纳米SiO2对环氧胶黏剂粘结性能以及耐蚀性能的影响。结果表明：改性纳米SiO2填充的环氧胶黏剂的剪切强度得到提高,最大增幅达到2MPa,耐蚀性能也得到提高。     

水稻播种用生物质胶黏剂的研究

介绍了一种用于制备水稻直播种纸的生物质胶黏剂,并对其合成工艺进行了研究。通过对玉米淀粉进行糊化、氧化、交联等化学改性,并以碱性稻草浆作为添加剂,研制出满足使用要求的生物质胶黏剂。探讨了氧化剂及交联剂对胶黏剂性能的影响,得出合成工艺条件为:氧化温度为 50℃,氧化时间为 120 min,氧化剂用量为 6% (占淀粉的质量分数),交联剂与淀粉的质量比为2:5,并对产物结构的红外光谱特征进行了分析。最后育种试验表明胶黏剂对种子生长无毒害作用。     

低有机氯含量PAE基纸张湿强剂的制备及性能评价

利用二乙烯三胺和己二酸为原料,对甲苯磺酸为催化剂合成聚酰胺,在聚酰胺和环氧氯丙烷的反应中加入三乙胺和阳离子改性剂,反应得到改性聚酰胺环氧氯丙烷(PAE)树脂,将其用作纸张湿强剂,进行浆内施胶得到了改性PAE树脂施胶纸张。通过傅里叶变换红外光谱(FTIR)及溶液稳定性测试对改性PAE树脂的结构和稳定性进行了表征,讨论了温度和三乙胺用量对有机氯含量的影响、三乙胺及阳离子改性剂用量对改性PAE树脂施胶纸张物理性能的影响。结果表明,当温度为50℃、三乙胺用量为7.4%(相对于反应物总质量)、阳离子改性剂用量为24.6%(相对于反应物总质量)时,制备的改性PAE树脂中有机氯含量为0.067%(相对于PAE树脂总质量),低于国家标准规定的0.7%,并可在室温下稳定放置。当改性PAE树脂添加量为质量分数1.6%,其浆内施胶效果最佳,浆内zeta电位为-1.2mV,纸张接触角为63.56°,改性PAE树脂施胶纸张与原纸相比干抗张指数、湿抗张指数、撕裂指数和耐折度分别提高了41%、13%、32.8%和27%,纸张物理性能明显增强。     

滑石粉的不同表面处理工艺对PVC/ABS/滑石粉合金性能的影响

采用钛酸酯偶联剂对滑石粉进行表面处理,考察了偶联剂用量、偶联剂与滑石粉的共混工艺和共混时间对聚氯乙(烯PVC)/丙烯腈-丁二烯-苯乙烯共聚(物ABS/)滑石粉合金力学性能和维卡软化温度的影响。结果表明:当偶联剂用量为滑石粉的1%~2%时,合金的综合力学性能最佳,维卡软化温度略有下降;以无水乙醇为溶剂共混滑石粉和钛酸酯偶联剂,可以保持甚至提高PVC/ABS/滑石粉合金的力学性能,并随着共混时间的增加合,金的力学性能和维卡软化温度先上升后下降。     

马尾松化学热磨机械浆酶法改性研究

利用漆树漆酶/介体体系对马尾松化学热磨机械浆进行生物酶处理及后续H2O2漂白,探索漆酶生物改性最佳工艺条件。结果表明,在漆酶用量为2.0 U/g,2,2’-连氮-二(3-乙基噻唑-6-磺酸)(ABTS)用量0.5%,酶处理温度50℃,酶处理时间60 min时,与对照浆相比,纸浆白度可提高3.0%ISO,抗张指数、撕裂指数分别提高22.5%、7.9%。纤维长度、粗度分析及扫描电镜谱图显示,漆酶处理只发生在纤维表面,有利于表面木素的降解溶出,从而提高了纸浆的白度和可漂性。     

Influence of talc genesis and particle surface on the crystallization kinetics of polypropylene/talc composites

Talc is a laminar silicate, considered as an excellent nucleating agent for polypropylene (PP) crystallization. However, properties of PP/talc composites depend on the morphology, size, and surface of mineral particles. In this sense, talc from several ores, having different morphology, imparts specific characteristics on these materials. Also, taking into account that PP‐talc adhesion is not necessarily good due to the apolar character of PP, talc surface has been modified in order to increase this parameter. In this work, the effects of talc genesis, geomorphologic aspects, and particle surface characteristics on crystallization of PP/talc composites are analyzed. Isothermal crystallization of PP/talc composites was studied by using differential scanning calorimetry, based on Avrami model. The final crystalline morphology of talc‐filled PP was analyzed by means optical microscopy. The results show that the blocky talc morphology favors even more the crystallization compared to the platy one, at the same particle size. Taking into account the surface treatment studied in this work, the talc surface is made hydrophobic and the particle delamination is favored. As a consequence, so‐modified talc is very effective in increasing the crystallization temperature of PP and the nuclei number that grow during the crystallization with respect to the untreated talc. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Improvement of ink and heavy metal removal from old corrugated container stock by alkali kneading

One of the possible ways to strengthen competitiveness of Kraft paper industry is to replace the expensive virgin unbleached kraft pulp (UKP) with old corrugated container (OCC), a cheaper and lower grade raw material. When OCC is utilized to produce kraft paper, the main problems are the impaired appearance of the products, and heavy metals and hazardous materials in the products caused by the printed ink and other contaminants. In order to improve the removal efficiency of ink and heavy metals from old corrugated container stock, the effect of adding alkali during kneading of OCC stock was investigated. It was found that adding NaOH and sodium silicate during kneading could improve detachment of ink from fiber surface and removal of it from stock and hence improve heavy metal removal from OCC stock. Since alkali addition improves ink detachment, effective residual ink concentration (ERIC) of pulp was decreased and brightness was increased. Tensile strength and tensile energy absorption (TEA) were increased with addition of alkali.     

MDPE/滑石粉/EOC复合材料力学性能的研究

以乙烯辛烯共聚物(EOC)和偶联剂改性的滑石粉(Talc)共混改性中密度聚乙烯(MDPE)制备复合材料,研究了Talc的表面处理工艺、粒径和添加量,以及EOC用量对复合材料力学性能的影响。结果表明:硅烷偶联剂对Talc的湿法表面处理较好,3000目滑石粉含量为5%,EOC加入量为2%时,复合材料的综合性能较好。     

Effect of talc surface treatment on the mechanical properties of composites based on PP/LDPE blend matrices

A study has been made of property optimization of a composite based on low density polyethylene and polypropylene (PP) blend matrices with talc modified by a titanate coupling agent. Analysis shows that the flexural properties improve with increasing content of both talc and polypropylene. However, the tensile moduli show a different behavior. Tensile strength is hardly affected by the filler content at PP percentages in the matrix above 50 percent. The surface modified talc gives rise to higher mechanical properties than the unmodified talc. This improvement is more noticeable as talc and PP percentages in the composite is increased. Scanning electron microscopy has shown the effect of the coupling agent at the filler/polymer matrix interphase and the greater affinity between talc and polypropylene.     

Effect of biobased and biodegradable nucleating agent on the isothermal crystallization of poly(lactic acid)

The effect of chemically modified thermoplastic starch (CMPS) on the thermal properties and isothermal crystallization kinetics of poly(lactic acid) (PLA) was studied by differential scanning calorimetry (DSC) and compared to that of granular starch and an inorganic nucleating agent, talc. Nucleated PLA showed an additional crystallization of PLA, which affected the melting temperature. The crystallinity and crystallization rate of PLA were considerably enhanced by addition of CMPS, even at 0.1% content, and the amount of the CMPS had little effect on the thermal properties and isothermal crystallization kinetics of PLA. The effect of CMPS as a nucleating agent was comparable to that of granular starch but slightly less than that of talc. However, CMPS can offer a fully biodegradable nucleating agent with no residues remaining for the biobased and biodegradable polymers.