椰壳纤维丝光处理的优化设计

研究了椰壳纤维的丝光处理,进行了正交设计,确定了椰壳纤维在NaOH溶液中的浸泡对复合材料力学性能的影响主要因素.实验结果表明:在NaOH溶液的质量百分浓度约为10%,浸泡时间36h、浸泡温度20℃的条件下,处理所得的椰壳纤维用于复合材料中效果最好.其中椰壳纤维的含量对复合材料的冲击性能影响最大.     

椰壳纤维丝光处理的优化设计EI

研究了椰壳纤维的丝光处理,进行了正交设计,确定了椰壳纤维在NaOH溶液中的浸泡对复合材料力学性能的影响主要因素.实验结果表明:在NaOH溶液的质量百分浓度约为10%,浸泡时间36h、浸泡温度20℃的条件下,处理所得的椰壳纤维用于复合材料中效果最好.其中椰壳纤维的含量对复合材料的冲击性能影响最大.     

氨基酸类保护剂的冻结特性及抑制冰晶机理研究

本文借助差式扫描量热法(DSC)研究了降温速率(5、10、20、50、100 ℃ /min)和溶液浓度(0.5、1、2、3、4 mol/L)对L－赖氨酸、L－脯氨酸、甘氨酸和L－丝氨酸等典型氨基酸类保护剂热物性参数的影响。研究结果表明:溶液浓度对低温保护剂溶液热物性参数的影响比降温速率的影响更加显著;在低溶液浓度(0.5mol/L和１mol/L)条件下,L－脯氨酸的未冻水含量高于其它3种氨基酸,表明在低浓度溶液中,Ｌ－脯氨酸的结合水能力更强,在高溶液浓度(2mol/L 和3mol/L)条件下,L－赖氨酸的未冻水含量高于其它3种氨基酸,因为在相同浓度溶液中,Ｌ－赖氨酸官能团浓度高于其它3种氨基酸,且其分子链较长,官能团自键合概率低,对冰晶抑制效果更强,表现出更高的未冻水含量。     

基于溶剂置换的壳聚糖水凝胶的构建及力学性能研究

采用碱液置换丙二醇的方法制备物理交联壳聚糖水凝胶,研究了碱液浓度及三聚磷酸钠（TPP）离子交联预处理对凝胶结构和力学性能的影响。SEM观察结果表明水凝胶微观结构为富有纳米纤维的三维网络结构,且离子交联预处理在一定程度上会影响水凝胶内部结构的形成。无侧限压缩测试和动态力学分析（DMA）结果显示,未经离子交联的水凝胶在NaOH溶液浓度≤4mol/L时,力学性能随碱溶液浓度增大而增加,在NaOH溶液浓度为4mol/L时获得最优的力学性能;TPP交联后再经NaOH溶液处理的水凝胶其力学性能有所下降,当NaOH溶液浓度为2mol/L时可获得最优的力学性能。采用的2种物理交联方式在水凝胶形成过程中具有竞争关系。     

铁尾矿在碱性环境下的溶解特性

采用球磨机将铁尾矿研磨成细粉，分别浸泡在不同浓度及温度的NaOH溶液和KOH溶液中，浸泡24 h后进行固液分离，并分别采用ICP-OES和XRD分析液相的化学组成和固相的矿物组成。结果显示，在NaOH和KOH溶液中溶出的主要成分是铁尾矿中的Si和Al,而Ca、Mg和Fe的溶解率均非常低，其溶解率顺序为Si>Al>>(Ca, Mg, Fe);Si、Al的溶解率均随溶液碱浓度的增大和溶液温度的升高而增加；当溶液浓度达到10 mol/L或温度达到80℃时，Si、Al的溶解率明显增大。铁尾矿中的大部分矿物在碱溶液中会发生溶解或转化，其中石英、钠长石和普通辉石大量溶解；方解石在高碱浓度溶液中转化为羟钙石；赤铁矿和斜绿泥石相对稳定，但赤铁矿在高温时会部分溶解。     

改性竹叶对水中刚果红的吸附性能研究

用NaOH改性后的竹叶粉作为吸附剂,采用静态吸附法,研究了NaOH浓度、竹叶粉投加量、pH、染料浓度和吸附时间等因素对改性竹叶(MBL)吸附刚果红的影响。结果表明:在NaOH浓度为20.00g/L的条件下,当溶液pH=7.0,MBL投加量为2.00g/L,吸附时间为120min时,MBL对100mg/L刚果红模拟印染废水(CRW)吸附效果最好,去除率可达96.29%,此时吸附量为48.14mg/g。吸附动力学研究表明,该吸附过程符合伪二级动力学模型,属于化学吸附。其等温吸附方程可以用Langmuir方程描述,表现为单分子吸附。     

溴水的膜吸收性能研究

研究了溴水的膜吸收分离性能,并采用回归正交试验设计方法优化溴水膜吸收工艺条件.以NaOH溶液作为吸收剂,采用PVDF中空纤维膜,研究了吸收时间、溴水温度、吸收液浓度及其流速等操作条件对溴水膜吸收性能的影响.结果表明:溴的吸收率随吸收时间的增加而增大,溴水膜吸收过程进料温度与传质系数之间符合阿伦尼斯关系.吸收液侧NaOH的浓度从0.003 mol/L增加至0.01 mol/L时,传质系数从4.75×10-4 cm/s增至6.02×10-4cm/s,对应的膜通量从2.4×10-3 kg/(m2·h)增至3×10-3 kg/(m2·h).吸收液的流体动力学条件对于溴水膜吸收过程通量无显著影响.采用回归正交试验确定的PVDF膜溴水膜吸收分离最佳工艺为:当NaOH吸收溶液浓度为0.01 mol/L,流量为2 L/h时,浓度为220 mg/L的溴水在进料温度为50℃、进料流速为22.24 cm/s的条件下,膜吸收通量达到6.17×10-3kg/(m2·h).     

甘蔗叶活化时的热解历程及其活性炭的研制

采用热重分析仪(TG-DTG)分析了NH4H2PO4活化甘蔗叶时的热解历程和活化反应机理,研究了活化剂浓度、液料比、浸泡时间、活化温度及活化时间等工艺因素对甘蔗叶活性炭样品得率、碘吸附值的影响,并运用扫描电子显微镜(SEM)对甘蔗叶及其活性炭样品进行了表征。结果表明,甘蔗叶制备活性炭的反应为4C+2NH4H2PO4→P2O3+CH4↑+CO2↑+2CO↑+2NH3↑+H2O↑甘蔗叶活性炭的碘吸附值随着活化时间的延长而增加,随着活化剂浓度、液料比、浸泡时间、活化温度的增加而呈现先增后减的变化规律;甘蔗叶活性炭的最优制备工艺条件为活化剂浓度2.5%(质量分数),液料比为5∶1,浸泡时间为20 h,活化温度为700℃,活化时间为60 min,所制备的活性炭样品具有丰富的管束结构,其得率和碘吸附值分别为30.9%、993.33 mg/g。     

Ca-B-Si体系LTCC材料腐蚀行为及腐蚀机理

LTCC材料在电镀和化学镀工艺中对酸/碱镀液的耐蚀性是低温共烧陶瓷(Low Temperature Co-fired Ceramics,LTCC)材料在实际应用中需要关注的重要特性。本工作研究了HCl、H₂SO₄和NaOH溶液(0.01～2.00 mol/L)和浸泡时间(10～300 min)对Ca-B-Si体系LTCC材料腐蚀行为的影响规律。结果表明，LTCC材料在不同的酸溶液中浸泡相同时间,样品的腐蚀失重量会随着酸溶液浓度增大呈现出先增大后减小的趋势,而在碱溶液中并未观察到明显的腐蚀现象。当盐酸溶液浓度为1.00 mol/L时,LTCC材料的失重最大为54.96%。当硫酸溶液浓度为0.10 mol/L时,LTCC材料的失重最大为8.80%LTCC材料中的CaB₂O₄和CaSiO₃晶相会与酸溶液发生溶解反应进而造成腐蚀,并且随着酸溶液浓度增大,反应后样品表面富Si蚀变层的形成速度更快,进而使LTCC材料在较高浓度酸溶液中的浸泡失重量减小。LTCC材料在1 mol/L盐酸溶液和...     

磷酸活化甘蔗叶制备活性炭的工艺研究

采用正交试验方法系统研究了活化剂、添加剂、活化温度、活化时间等因素对磷酸活化甘蔗叶制备活性炭的得率、亚甲基蓝吸附值的影响,并利用SEM对样品进行了表征。结果表明,磷酸活化甘蔗叶制备活性炭的最佳工艺为:将甘蔗叶浸泡于6%添加剂1及1%添加剂2、体积浓度为35%的磷酸溶液中,浸泡12h后,在673K条件下活化40min,所制得的活性炭的微观孔结构排列整齐,活性炭的得率和亚甲基蓝吸附值分别为47.05%、202.50mg/g,其中亚甲基蓝吸附值为国家标准GB/T 13803.2-1999活性炭一级品的1.5倍。     

Toward the control of thickness and uniformity in the coating of TiO2-P25 on glass

ABSTRACT

The deposition of TiO₂-P25 on Pyrex glass is studied in order to propose a procedure for obtaining uniform and adherent thin films with a controlled thickness in the range between fractions of micrometer to a few tens of micrometers. Different deposition methods such as spray-coating, dip-coating, and drop-coating of liquid suspensions of TiO₂-P25 powder are considered. The effects of pretreatment of the glass support, as well as postdeposition steps such as drying condition and thermal treatment, are also reported. A basic glass pretreatment and an acidic TiO₂ suspension are chosen for an optimized adherence of the film. Drop-coating, associated with a slow drying under 55% relative humidity and a high-temperature thermal treatment is the method of choice to prepare coated glass slides in a large range of film thicknesses.     

Tensile behaviours of some high performance filaments after NaOH treatment

Quartz, aramid, and glass filaments were treated by NaOH solution with various concentrations and periods. The outward appearance of the treated filaments was shown.The investigation revealed that higher density of NaOH solution and prolonged treating time would cause accelerated degradation of the aramid filament; when different NaOH concentrations were involved, the decrease rate of the quartz fibre strength after 3 weeks’ treatment was not as distinctive as that for the aramid fibre; it seems that both NaOH concentration and the treating time used in this research played minor roles on the tensile strength decrease of the glass fibre.     

Influence of fibre treatment and glass fibre hybridisation on thermal degradation and surface energy characteristics of hemp/unsaturated polyester composites

The effect of fibre treatment on the thermal degradation and surface energy characteristics of hemp fibre reinforced unsaturated polyester (HFRUP) composites was investigated by means of a thermogravimetric analyser (TGA) in a nitrogen atmosphere and contact angle measurement. In order to modify the fibre/matrix interface, NaOH treatment and glass fibre hybridisation were employed. HFRUP composites were compared to the unreinforced UP, NaOH treated hemp and glass fibre hybridised hemp/UP composites. TGA test results show that the weight loss for all samples occurred between 200 and 415 °C. The unreinforced UP had a maximum weight loss of 1.011%/°C. For the HFRUP composites, the maximum rate of weight loss was 0.81%/°C. For the NaOH treated and glass fibre hybridised hemp/UP composites, the maximum rate of weight loss was 0.78%/°C and 0.79%/°C, respectively. The effect of fibre treatment on the surface energy of studied samples and their dispersive and polar components were also investigated. Surface energy characteristics obtained from contact angle measurement revealed that for unreinforced UP, the contact angle measured with glycerol is 49.37°. For hemp/UP composites, the contact angle is 76.05°. For NaOH treated hemp/UP composites sample, the contact angle was recorded 78.89°, higher than untreated one. For hemp/CSM/UP specimen, the contact angle was recorded 69.80°. Both TGA and contact angle results indicated that surface treatment and glass fibre hybridisation led to better thermal stability and the wetting behaviour of hemp/UP composites.     

活化细菌纤维素的结构与性能

分别采用乙二胺和NaOH对BC进行活化,以改善BC在离子液体中的溶解性能,通过正交实验优化了其活化工艺,并研究了活化前后BC的红外光谱、结晶结构、结晶度、聚合度和热分解性能,以及在离子液体[BMIM]Cl中的溶解性能。结果表明,乙二胺活化的最佳工艺为浓度14%,温度60℃,时间90min,氢氧化钠活化的最佳工艺为浓度10%,温度40℃,时间480min。活化后BC分子结构中的氢键作用力减弱,结晶结构发生不完全的转变,结晶度和聚合度下降,热稳定性提高,化学试剂的可及度增加,在离子液体中的溶解时间显著缩短。     

NaBH_4前处理桦木化学镀镍制备木质电磁屏蔽复合材料

以桦木单板为基材,利用NaBH4处理后直接进行化学镀镍制备电磁屏蔽复合材料。研究NaBH4浓度和浸渍时间、施镀时间和NaOH浓度对表面电阻率的影响。分别采用扫描电镜(SEM)和X射线衍射(XRD)分析对比NaBH4前处理和胶体钯活化所得复合材料的表面形貌和组织结构,利用频谱仪和直拉法分别测定电磁屏蔽效能和镀层附着强度。结果表明:利用4g/L的NaOH配制3g/L的NaBH4溶液,前处理5~10min,化学镀镍20min,此条件下制备的复合材料的表面电阻率低于150mΩ/cm2,在9kHz~1.5GHz频段,电磁屏蔽效能高于60dB。NaBH4前处理所得复合材料的电磁屏蔽效能高于胶体钯活化;从表面形貌上观察,两种方法均可得到均匀、连续和致密的镀层,镀层完全覆盖了木材表面,具有金属光泽;XRD分析表明,NaBH4前处理所得镀层厚些,且结晶状态更佳,木材和镀层之间为物理结合;强度测试显示两种方法所得镀层均与木材表面结合牢固。     

Preliminary ageing study of bioactive glass in a cell culture model

In the past we sometimes found poor cell morphology and relatively low biochemical values for osteoblast cultures on bioactive glass. These observations were not caused by any external causes. Our hypothesis is that the surface reactivity of polished bioactive glass slides might decrease slowly due to the influence of (air-) humidity during storage under normal room conditions. In the present study we investigated the ageing of bioactive glass stored under room conditions as well as bioactive glass stored under dry conditions. We also compared the results with glass slides stored for about one year with freshly obtained bioactive glass slides, both stored under dry conditions. We evaluated several histological and biochemical parameters obtained from osteoblast cultures on the differently preserved glass slides. The results showed that bioactive glass probably maintains its bioactive nature when stored under dry conditions. We found different biochemical values for bioactive glass prepared with a new oven and elaborated with new polishing techniques in comparison with previously prepared batches of bioactive glass. These results indicate that different bioactive glass batches with identical composition may not be identical in terms of bioactivity.     

空心玻璃微球化学镀镍前处理工艺的研究

针对空心玻璃微球化学镀镍,研究了先偶联、再活化的前处理工艺.探讨了偶联处理对活化效果的影响,并通过正交试验确定了最佳偶联条件;采用优化的前处理工艺,再进行化学镀镍,得到镍包覆空心玻璃微球,分别使用扫描电镜(SEM)和X射线能谱仪(EDS)对镀镍层的形貌结构和成分进行了表征.研究发现:空心玻璃微球经过偶联处理以后对钯的吸附能力提高了很多,使得化学镀镍中微球表面的活性点大大增加,得到了包覆完整、均匀、致密的镍镀层.     

Physical characterization of E-glass fibres treated with alkylphenylpoly(oxyethylene) alcohol — fibres conditioned in solutions of different pH

The adsorption of alkylphenylpoly(oxyethylene)alcohol on E-glass fibres was characterized by X-ray photoelectron spectroscopy, by the Wilhelmy plate method and by streaming-potential measurements. In this study, the glass fibres were conditioned in solutions of different pH. The acid resistance of the E-glass fibres was studied by treating the material with H₂SO₄. During the acid treatment the surface composition, namely the Si/Al-ratio, was changed, presumably because the aluminium ions were leached out of the glass structure. The alkaline resistance was studied by treating the material with NaOH. The Si/Al-ratio was unaffected by these moderate alkaline solutions. The effect of the surface conditioning in solutions of different pH seemed to be greatest for the acidic solutions giving rise to an increased adsorption of the surfactant on the glass-fibre surface.     

Effective surface pretreatment of hollow glass microspheres via a combined KF roughening and alkali washing strategy for the following metallization

Surface roughening of hollow glass microspheres (HGMs) is a necessary step determining their adhesion ability with the following electroless plated metallization coating. In this paper, a new KF roughening and alkali washing strategy was proposed to replace HF roughening as a surface pretreatment for the following electroless plating metallization. In order to remove the byproduct of K₂SiF₆ from the roughening reaction of KF with HGMs, NaOH washing and KOH washing were conducted, the former of which was found to dissolve K₂SiF₆ effectively. The effects of KF roughening temperature, alkali concentration and HGMs loading on the recovery ratio, phase composition, surface morphology and performance of HGMs were investigated, through which such a pretreating strategy was found to not only decrease the damage ratio of HGMs compared to that by HF roughening, but also render the metallized HGMs a competitive absorbing ability for the electromagnetic wave in X-band and Ku-band. Finally, the related surface treatment and electroless plating mechanism were discussed. This paper illustrates successfully a new pretreatment strategy for development of lightweight HGMs-supported functional materials.     

基于NaOH预处理的废纸纤维发泡材料工艺及配方研究

通过2种途径对废纸纤维发泡材料的工艺配方进行了优化,以获得性能更好的废纸纤维发泡材料。一是对废纸纤维原料进行NaOH预处理,研究了NaOH预处理对发泡材料性能的影响;二是基于NaOH预处理,采用微波加热发泡工艺改善了废纸纤维发泡材料的性能。结果表明:NaOH预处理较大程度上改善了废纸纤维发泡材料的发泡倍率、密度及缓冲性能。试验确定了废纸纤维预处理的最佳条件和基于NaOH预处理的废纸纤维发泡材料的最佳工艺配方。