三氧化二锑-硅灰石复合填料的制备及在聚丙烯中的填充性能

以硅灰石、三氧化二锑为主要原料,采用化学沉淀法在硅灰石表面包覆纳米三氧化二锑,制备一种无机复合型阻燃粉体材料,并用硅烷1113和硬脂酸对这种复合粉体进行表面改性后填充聚丙烯制备复合阻燃材料。采用扫描电镜、粒度仪、白度仪、X射线衍射等手段对改性粉体材料表面状况进行了表征,并检测了填充聚丙烯材料的力学性能、热学性能及垂直燃烧和水平燃烧阻燃性能。结果表明:硅灰石表面均匀的包覆了一层纳米三氧化二锑;其水平燃烧时间由90s降到30s,燃烧长度由75mm降到20mm,垂直燃烧时间由60s降到10s,由不具阻燃性升高到阻燃级别为V-2。     

锑掺杂氧化锡-硅灰石复合粉体的制备与表征

为了改善硅灰石的导电性,对硅灰石粉体的表面包覆改性进行研究;以硅灰石粉为原料,四氯化锡和三氯化锑为沉淀包覆剂,采用化学沉淀法制备锑掺杂氧化锡-硅灰石复合抗静电材料;研究不同工艺条件对该复合粉体体积电阻率的影响,采用透射电子显微镜、X射线能量色散谱、白度仪、粒度仪、比表面积仪等进行表征。结果表明,包覆后硅灰石白度由91.7%减小为90.5%,中位粒径由10.81μm增大为11.46μm,比表面积由1.406 8 m2/g增大为3.653 2 m2/g,体积电阻率由3.36×1010Ω·cm减小为0.85×105Ω·cm。     

硅灰石表面无机改性及其在聚丙烯中的应用

采用非均匀成核法,通过在硅灰石表面包覆硅酸铝对硅灰石进行了无机改性。扫描电镜（SEM）和X射线衍射（XRD）等测试表明,无机改性硅灰石颗粒表面粗糙,包覆着许多纳米硅酸铝粒子;通过BET比表面积分析仪测定,比表面积提高200%以上;红外光谱（FT-IR）测试表明,无机改性后硅灰石表面羟基增多;白度测试表明,无机改性硅灰石...     

非均匀成核法制备硅酸铝-硅灰石复合粉体材料

以硅灰石为原料,硫酸铝和硅酸钠为包覆剂,采用非均匀成核法制备一种硅酸铝-硅灰石复合粉体材料,研究搅拌速度、反应温度、反应时间、硫酸铝溶液浓度和滴加速度等工艺条件对复合粉体制备的影响。结果表明,控制机械搅拌速度为300~400 r/min,反应温度为80℃,反应时间为30 min,硫酸铝溶液浓度为0.1 mol/L,滴加速率为1~2 mL/min,可以实现硅酸铝以非均匀成核形式沉积在硅灰石表面,包覆硅酸铝后硅灰石白度提高,粒度增大,比表面积提高200%以上。     

硅灰石表面改性及其在聚丙烯中的应用

采用硅烷对硅灰石进行了表面改性实验,将活化后的粉体加入聚丙烯材料中,研究了硅烷改性对聚丙烯/硅灰石复合材料性能的影响。通过对改性前后粉体吸油值及红外光谱分析以及对填充聚丙烯材料新鲜断面的扫描电镜分析,研究硅烷改性硅灰石的效果和改性机理。结果表明:硅烷偶联剂适宜用量为硅灰石质量的0.8%~1.2%,改性温度为80℃,时间为15~20 min。表面改性可以显著提高聚丙烯/硅灰石复合材料的拉伸强度、弯曲强度、弯曲模量、热变形温度等性能指标。     

纳米Mg(OH)_2包覆粉煤灰空心微珠复合粉体的制备及表征

为了解决粉煤灰空心微珠白度不高的问题,以粉煤灰空心微珠煅烧样为原料,以NaOH和MgSO_4为包覆剂,采用非均匀形核法制备了一种纳米Mg(OH)_2包覆粉煤灰空心微珠复合粉体材料;采用白度仪、粒度仪、比表面积仪、X-射线衍射仪(XRD)、扫描电子显微镜(SEM)对复合粉体进行表征;研究不同工艺条件对复合粉体白度的影响。结果表明:当包覆量(Mg(OH)_2与粉煤灰空心微珠质量之比)为50%,包覆剂双加,反应温度为80℃时,空心微珠白度由27.1%提高至51.2%,粒径D98由60.81μm增大至66.72μm,比表面积由4.512 m~2/g增大到31.697 m~2/g。XRD、SEM测试结果表明:空心微珠表面包覆了纳米片状Mg(OH)_2。该复合粉体有望应用在塑料填料和污水处理领域。     

无机矿物填料表面纳米化修饰及性能表征

采用化学方法对无机矿物填料表面进行包覆改性，制备出具有表面纳米化结构的复合矿物颗粒，有效地改善了原有颗粒的表面形貌，提高了比表面积，通过搅拌磨湿法研磨，讨论了包覆颗粒与基体的结合方式，初步证明了包覆颗粒与基体的结合方式为化学吸附而非物理吸附，两者结合牢固，包覆层不易脱落，包覆矿物颗粒在聚丙烯（PP）中填充，其复合材料的力学性能有较大的改善。     

水镁石基复合阻燃剂的制备及在EVA材料中的应用

采用化学复合方法制备出水镁石基复合阻燃剂,SEM、XRD和EDS测试表明复合阻燃剂颗粒表面粗糙,水镁石表面包覆着许多超细氧化锌粒子,通过BET测定,比表面积由包覆前的10.1499 m2/g提高到13.6762 m2/g。由复合阻燃剂填充的EVA材料,氧指数可达41.8,拉伸强度达13.4 MPa,断裂伸长率达193%,较水镁石原料及水镁石和氧化锌机械混合样的阻燃性能和力学性能有显著提高。TG和DTA热分析表明,复合阻燃剂可提高复合材料的分解温度和燃烧残留率,能有效抑制聚乙烯主链裂解,增强复合材料的热稳定性。     

氢氧化镁的改性及其填充聚丙烯复合材料的燃烧性能和结晶行为的研究

研究了硅烷改性剂对氢氧化镁(MH)的表面改性和其填充聚丙烯(PP)复合材料的阻燃性能和结晶行为.用FTIR、XRD和SEM对改性前后MH的结构和形貌进行了分析.结果表明,硅烷处理剂包覆在MH粉体的表面,有效地降低MH粉体的表面能,提高了MH在干态下的分散性.DSC、POM和LOI对PP/MH复合材料的结晶行为和燃烧性能进行了研究.结果表明,未改性的MH对PP有异相成核作用,使结晶峰温度升高;而表面改性剂削弱了填料的异相成核作用.POM结果暗示了MH粒子在基体中的分散性对PP球晶的晶粒形貌和晶粒尺寸起着十分重要的作用.改性后的MH能进一步提高复合材料的LOI.     

高岭土的机械化学改性及其对聚乙烯的补强性能

采用机械研磨和表面改性的方法,制备了硅烷接枝高岭土粉体。利用粒度分析仪、红外光谱分析和沉降性能测试等进行表征。研究结果表明:机械研磨提高了硅烷与高岭土的反应活性,使其在液体石蜡中具有良好的分散稳定性,与直接改性高岭土相比,沉降体积由3.2mL提高到7.6mL。将高岭土原矿、直接改性高岭土和磨剥改性高岭土分别与聚乙烯熔融共混制备复合材料。研磨改性高岭土对聚乙烯具有良好的补强性能,并且在填充量为10份时达到最佳,材料的拉伸强度较纯聚乙烯提高了3.7MPa。     

基体诱导法制备碳纳米管/云母复合导电粉

基体诱导法制备碳纳米管(CNT)/云母复合导电粉, 即用聚乙烯醇(PVA)或聚丙烯酰胺(PAM)对云母进行处理, 将处理后的云母与CNT分散液混合, 使CNT吸附在云母表面. 测试复合导电粉的体积电阻率(ρ)发现, CNT含量为1.0wt%时, CNT/云母的ρ为2.0×10⁴Ω·cm, 而用PVA修饰的云母制备CNT/云母, 体积电阻率达到86.6Ω·cm. 运用XPS、SEM对复合导电粉进行表征. 结果表明当云母表面经PVA修饰后, 能改善CNT在其表面的吸附和分散, 使CNT/云母的体积电阻率明显降低.     

界面改性对钛酸铅／环氧树脂压电复合材料性能的影响

采用ＫＨ－５５０对钛酸铅粉末进行表面处理。通过对ＰＴ／环氧树脂和处理ＰＴ／环氧树旨两种压电复合材料的压电应变常数,耐热性和耐冲击强度的测定和对比,研究了界面改性对压电复合材料的压电性能的影响。结果表明：通过界面改性,可以明显提高复合材料的耐热性和耐击穿强度,耐对饱和极化时的压电应变常数无影响。     

Mechanical and thermal properties of lightweight geopolymer composites

This research has investigated the properties of thermally insulating geopolymer composites that were prepared using waste expanded polystyrene as lightweight aggregate. The geopolymer matrix was synthetized using metakaolin and an alkaline activating solution. To improve its mechanical properties, this matrix was modified by the addition of an epoxy resin to form an organic-inorganic composite. Moreover, in order to reduce drying shrinkage marble powder was used as an inert filler. The materials obtained were characterized in terms of physico-mechanical properties, thermal performance and microstructure. The geopolymer expanded polystyrene composite have improved properties compared to Portland cement-based materials, with higher strengths and lower thermal conductivity. The research demonstrates the manufacture of sustainable lightweight thermally insulating geopolymer composites using waste expanded polystyrene.     

Study on the Carbonyl Iron Powder Based Nano-Composite Radar Wave Absorbing Coatings

With the rapid development of stealth technique, carbonyl iron powder is regarded as an ideal radar absorbing material. In this paper, radar absorbing properties of carbonyl iron powder was investigated by using nano composite and macroscopic multi- layer composite approach. The machine- chemistry composite methods were employed during the experiment to produce nano composite absorbent. Two carbonyl iron powders named HP1, HP2 and nano powder named HP3 were employed. Absorbents were obtained by adding 10% HP3 powder with average size of 28 nm to the HP1 and HP2 carbonyl iron powders by weight respectively. By a series of composite techniques, sample plate with the radar absorbing coating was prepared. Compared with the single coating, the wave absorbing properties were significantly improved. The working band in which the wave reflectivity was less than 5 db was 4.8 ～ 18 GHz with the coating thickness of 1.0 mm. The lowest reflectivity was found to be 12.34 db at 8 GHz. The wave absorbing coating with thin thickness,broadband and strong absorbing properties was obtained.     

SML超分散剂的合成及在复合材料中的应用

介绍了超分散剂对粉体改性机理,并合成了SML超分散剂,考察了其改性超细CaSO4粉体后的活化指数,同时探讨了SML超分散剂对PE/超细能的影响,最后通过SEM观察了复合材料断面形貌.结果表明,SML超分散剂优于F-2分散剂.在其用量为3%时,活化指数可达97%,复合材料的拉伸强度、冲击强度、弯曲强度分别提高了28.7%、20.7%、4.9%.     

Effects of temperature and clay content on water absorption characteristics of modified MMT clay/cyclic olefin copolymer nanocomposite films: Permeability,dynamic mechanical properties and the encapsulated organic device performance

In the present study, amino-silane modified layered organosilicates were used to reinforce cyclic olefin copolymer to enhance the thermal, mechanical and moisture impermeable barrier properties. The optimum clay loading (4%) in the nanocomposite increases the thermal stability of the film while further loading decreases film stability. Water absorption behavior at 62 °C was carried out and compared with the behavior at room temperature and 48 °C. The stiffness of the matrix increases with clay content and the recorded strain to failure for the composite films was lower than the neat film. Dynamic mechanical analysis show higher storage modulus and low loss modulus for 2.5–4 wt% clay loading. Calcium degradation test and device encapsulation also show the evidence of optimum clay loading of 4 wt% for improved low water vapor transmission rates compared to other nanocomposite films.     

Development of modified release diltiazem HCl tablets using composite index to identify optimal formulation

This article reports the preparation of tartaric acid treated ispaghula husk powder for the development of modified release tablets of diltiazem HCl by adopting direct compression technique and a 3² full factorial design. The modified ispaghula husk powder showed superior swelling and gelling as compared to untreated powder. Addition of compaction augmenting agent such as dicalcium phosphate was found to be essential for obtaining tablets with adequate crushing strength. In order to improve the crushing strength of diltiazem HCl tablets, to modulate drug release pattern, and to obtain similarity of dissolution profiles in distilled water and simulated gastric fluid (pH 1.2), modified guar gum was used along with modified ispaghula husk powder and tartaric acid. A novel composite index, which considers a positive or a negative deviation from an ideal value, was calculated considering percentage drug release in 60, 300, and 540 min as dependent variables for the selection of a most appropriate batch. Polynomial equation and contour plots are presented. The concept of similarity factor (f₂) was used to prove similarity of dissolution in water and simulated gastric fluid (pH 1.2).     

纳米金刚石-陶瓷结合剂复合粉体的高分子网络凝胶法制备与烧结

采用高分子网络凝胶(P-G)法制备了纳米金刚石-陶瓷结合剂的复合粉体, 通过压制成型, 低温烧结, 获得了纳米金刚石-陶瓷结合剂的复合烧结块体试样; 同时与采用高温熔融法制备的陶瓷结合剂, 再加入纳米金刚石机械混合后烧结制备的复合烧结块体试样进行对比。通过X射线衍射分析了试样的物相构成, 借助场发射扫描电镜对试样断口进行了显微形貌观察, 采用三点弯曲法测试了试样的抗折强度, 利用阿基米德原理测试了试样的密度和气孔率。结果表明, 采用高分子网络凝胶法可以获得纳米金刚石均匀分散的纳米金刚石-陶瓷复合粉体, 经过800 ℃/2h烧结后试样的抗折强度为60.41 MPa, 密度为1.81 g/cm³, 气孔率为15.67%; 而采用高温熔融法+纳米金刚石的工艺获得的纳米金刚石-陶瓷结合剂烧结后试样, 其抗折强度、 密度和气孔率分别为46.48 MPa、 2.23 g/cm³和11.75%, 其显微结构中可见明显的纳米金刚石团聚体。高分子网络凝胶法可以成为超精磨削用纳米金刚石-陶瓷磨具制备的新方法。     

TiN/聚吡咯纳米复合材料的制备及表征

采用氨解法制备了纳米氮化钛(TiN)粉体,对纳米TiN粉体进行表面改性,使其均匀分散到吡咯单体中.采用原位聚合法制备了TiN/聚吡咯(PPy)纳米复合材料.对合成的复合材料用X射线衍射(XRD)、透射电镜(TEM)、傅立叶变换红外光谱(FT-IR)、四探针测试仪等方法进行了表征与检测.结果表明:PPy成功地包覆在TiN纳米颗粒表面,形成了纳米TiN/PPy复合材料.复合材料具有优良的电性能.