Morphology and performance of potassium titanate whisker-reinforced polypropylene composites

Titanate whisker-reinforced polypropylene composites were prepared in a twin-screw extruder followed by injection molding. The whiskers were surface treated with tetrabutyl orthotitanate prior to blending. The static and dynamic mechanical properties, impact strength, and thermal properties of the composites were investigated. Static tensile measurements showed that the tensile strength and Young's modulus of the composites increased with increasing whisker content. However, the Izod impact tests indicated that the impact strength of longitudinal samples remained unchanged with the addition of whisker up to 10 wt %. Thereafter, it shows a continuous decrease with increasing whisker content. The thermogravimetric and dynamic mechanical tests demonstrated that the heat-resistance and thermooxidative stability for the composites also increased with increasing whisker content. Scanning electron microscopic observations revealed that the whiskers within the composites were oriented uniformly. The experimental data were compared with the well established mechanical models to evaluate the reinforcing efficiency. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 431–439, 1998     

Tribological behavior of polyetheretherketone composites containing short carbon fibers and potassium titanate whiskers in dry sliding against steel

Polyetheretherketone (PEEK) composites reinforced by short carbon fibers (SCF) and potassium titanate whiskers (PTW) were prepared using twin‐screw extrusion compounding and injection molding. The tribological properties of hybrid composites were investigated in dry sliding condition against steel. The effects of filler contents on the wear behavior were studied. It was found that the hybrid composite showed an excellent tribological property in dry sliding condition. Applied load had great effect on the tribological behavior of the composites. In most cases, the friction coefficient of the composite decreased with the load rising. The composites with higher CF contents showed outstanding tribological performances at low load but could worsen the wear behavior at high load. Because of the positive effect of PTW, high PTW loading composites presented low wear rate at low load. At high loads, the composites with lower PTW contents had better wear resistance. The scanning electron microscopy (SEM) observation revealed that abrasion wear was attributed to the lower wear resistance of the high PTW content composite at high load. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

钛酸钾晶须及滑石粉复合增强聚丙烯

采用钛酸钾晶须和滑石粉协同增强聚丙烯,并添加POE作为增韧剂研究聚丙烯复合材料的性能.实验发现:钛酸钾晶须对聚丙烯有很好的增强增韧效果,采用PP-g-MA做增容剂和表面处理过的晶须,具有更好的实验效果.聚丙烯复合材料的拉伸模量和弯曲模量均随钛酸钾晶须含量增加而显著上升.此外,加入滑石粉在不大幅度降低聚丙烯拉伸强度的同时,提高聚丙烯的耐热性,进一步改善体系的流动性,降低成本.     

Mechanical and thermal properties of polycarbonate composites reinforced with potassium titanate whiskers

Polycarbonate (PC) composites reinforced with potassium titanate (K₂Ti₆O₁₃) whiskers were blended in a twin‐screw extruder followed by injection molding. The surface of whiskers was treated with tetrabutyl orthotitanate prior to blending. The effects of potassium titanate whisker additions on the tensile, impact, and thermal properties of PC were investigated. Tensile tests showed that the stiffness of composites markedly improved with increasing whisker content. However, potassium titanate whiskers were ineffective to reinforce PC because these whiskers promoted chemical decomposition of PC matrix during compounding. Consequently, the torque values of PC/K₂Ti₆O₁₃ composites were much lower than that of PC. Moreover, torque measurements revealed that titanate coupling agent also facilitated decomposition of PC during blending. The mechanisms responsible for the degradation of PC matrix of the surface‐treated PC/K₂Ti₆O₁₃ composites are discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 501–508, 1999     

钛酸钾晶须的表面改性及其在隔热卷材涂料中的应用

利用硅烷偶联剂KH-570对表面无机包覆SiO2前、后的六钛酸钾晶须(PTW)进行有机表面改性,比较了硅烷偶联剂改性无机包覆SiO2处理前、后的PTW对卷材涂料隔热性能的影响.采用红外光谱(IR)、热重分析(TG)方法对改性前后的PTW进行了表征.结果表明,SiO2以化学键键合在PTW表面,KH-570在PTW表面形成了有机包覆层.涂膜隔热性能测试结果表明,以9%SiO2包覆处理后再用偶联剂KH-570改性的PTW能明显改善隔热卷材涂料的隔热性能,其热反射率达到75.4%,比不含PTW的漆膜提高了34.4个百分点,比含直接用偶联剂KH-570改性的PTW的漆膜提高了12.8个百分点.     

Dynamic mechanical properties of whisker/PA66 composites at high strain rates

PA66 reinforced with potassium titanate whisker (TKW) treated with silane coupling agent were prepared using a twin-screw extruder. The quasi-static and dynamic mechanical properties were investigated. Addition of 40 wt % TKW to PA66 improves all the investigated properties. The high-speed dynamic tests with TKW/PA66 were carried on split Hopkinson pressure bar (SHPB). The loading pulses in SHPB experiments were precisely controlled to ensure that the composite specimens deformed at a nearly constant strain rate under dynamically equilibrated stress during dynamic compression. The constitutive curves and equations at high strain rates have been obtained. TKW/PA66 composites show 20-100% increase on reference modulus and 20% increase on compression strength.     

Mechanical properties and sliding wear behavior of potassium titanate whiskers‐reinforced poly(ether ether ketone) composites under water‐lubricated condition

Polyetheretherketone (PEEK) composites reinforced with potassium titanate whiskers (PTW) were compounded using a twin‐screw extruder followed by injection molding. The effects of PTW on the mechanical properties, crystallization performances and wear behaviors of PEEK under water lubrication have been investigated. It was denoted that the yield strength, Young's modulus, and microhardness of the composites increased with increasing whisker content, but the elongation at break and the impact strength showed decreasing trend. It was revealed that the inclusion of PTW could effectively reduce the friction coefficient and enhance the wear resistance of the PEEK. The DSC tests showed that the crystallinity of the composite slightly decreased with the addition of PTW, which might imply that the crystallinity of PEEK was not the dominant factor that influenced the wear properties of the composites. The enhancement on the wear resistance was attributed to the reinforced effect of PTW on PEEK. The wear mechanism changed from fatigue wear into mild abrasive wear when the PTW was added into PEEK. The lowest wear rate 9.3 × 10^?8 mm³/Nm was achieved at 10 wt % PTW content. However, excessive whiskers would cause severe abrasive wear to the composite. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Microstructural and mechanical characteristics of compatibilized polypropylene hybrid composites containing potassium titanate whisker and liquid crystalline copolyester

Maleic anhydride (MA) compatibilized polypropylene (MPP) hybrid composites reinforced with potassium titanate whiskers (K₂Ti₆O₁₃) and liquid crystalline polymer (LCP) were prepared in a twin-screw extruder followed by injection molding. The surface of whiskers were treated with tetrabutyl orthotitanate before blending. Scanning electron microscopic (SEM) examination showed that elongated LCP fibrils are formed in the skin section of hybrids reinforced with whiskers of various concentrations. Consequently, the hybrids reinforced with both LCP fibrils and whiskers exhibited anisotropic mechanical properties. Tensile test showed that longitudinal Young’s modulus and tensile strength of hybrids tend to increase with increasing whisker content. Moreover, the stiffness and tensile strength of hybrids were higher than those of MPP/K₂Ti₆O₁₃ composites. Such enhancement in mechanical properties resulted from the compatibilizing effect of MA-grafted-PP, and from the hybrid reinforcing effect of LCP fibrils and K₂Ti₆O₁₃ whiskers. Torque measurements revealed that LCP addition is beneficial in reducing the melt viscosity of MPP/K₂Ti₆O₁₃/LCP hybrids. The results of SEM observations generally correlate well with the mechanical measurements. The effects of MA compatibilization on the microstructure and mechanical properties of hybrids are discussed.     

Mechanical and thermal properties of poly(acrylonitrile–butadiene–styrene) copolymer reinforced with potassium titanate whiskers

Potassium titanate (K₂Ti₆O₁₃) whisker treated with tetrabutyl orthotitanate was used to improve the mechanical and thermal properties of the poly(acrylonitrile–butadiene–styrene) (ABS) copolymer. The composites were prepared in a twin‐screw extruder followed by injection molding. Static tensile measurements showed that both the modulus and breaking stress of ABS/K₂Ti₆O₁₃ composites increase considerably with increasing whisker content; the strain at break of ABS was almost unaffected by the incorporation of a whisker content up to 15 wt %. Izod impact tests indicated that the composites showed a decrease in the impact strength with increasing whiskers content. Thermogravimetric analysis showed that the K₂Ti₆O₁₃ whisker additions have little effect on the thermooxidative stability of ABS. Scanning electron microscopic observations revealed that the whiskers were aligned along the melt‐flow direction in the thin surface layer, whereas the whiskers were oriented randomly as well as perpendicular to the injection direction in the thick core region of the composites. The Tsai–Halpin equation was used to evaluate the moduli of the ABS/K₂Ti₆O₁₃ composites. The theoretical calculations generally correlated well with the experiment data by assuming K₂Ti₆O₁₃ whiskers to have an aspect ratio of 12. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2985–2991, 1999     

Influence of potassium titanate whisker on the mechanical properties and microstructure of calcium aluminate cement for in situ combustion

This study investigated potassium titanate whisker-reinforced calcium aluminate cement (CAC)-based composites, and evaluated the influence of the quantity (0–5% of the weight of the binder) of potassium titanate whiskers on the mechanical properties of hardened cement mortar. X-ray diffraction analysis and Scanning electron microscopy (SEM) were employed to determine the phase compositions and micro-morphology of the cement composites, respectively. Experimental results indicated that the addition of potassium titanate whisker exhibits significant potential to improve the tensile strength and toughness of cement mortars. The compressive and tensile strengths of samples cured at 50 °C were increased by 46.90 and 74.10%, and the tensile strength samples under high-temperature treatment increased by 113.67%, with the addition of 4% potassium titanate whisker. Typical cement slurry properties, such as basic rheology, free water, and fluid loss could maintain stability when added with 0–5% dosages of potassium titanate whiskers. SEM analysis indicated that the whisker could increase the toughness of oil cement, which contributed to whisker pullout and whisker-cement coalition pullout in the cement matrix.     

我国氯化聚乙烯的研究进展

综述了近年来我国氯化聚乙烯(CPE)的技术进展及改性研究,介绍了氯化聚乙烯的生产现状及市场需求,指出了我国氯化聚乙烯的发展方向。     

不同晶须改性聚丙烯的性能研究

研究了碱式硫酸镁(M-HOS)和钛酸钾(K2Ti6O13)晶须填充改性PP热变形温度、流动性能和力学性能等。结果表明,这两种晶须均能有效地提高PP热变形温度,同时也能改善其力学性能。镁盐和钛酸钾晶须的最佳含量均为30%,此时PP热变形温度分别提高到151.8℃和146.5℃。     

硅钙镁晶须填充聚丙烯复合材料的性能研究

在啮合同向双螺杆挤出机中制备了聚丙烯（PP）/硅钙镁（SCM）晶须复合材料,研究了硅烷偶联剂用量、SCM晶须含量对复合材料力学性能以及熔体流动性能的影响。实验结果表明,当硅烷偶联剂用量占晶须的2 ％（质量分数,下同）时,PP与SCM晶须的配比为80/20（质量比,下同）时,PP/SCM晶须复合材料的拉伸强度、弯曲强度和冲击强度等综合力学性能最佳。     

Rheological behaviour of titanate coated mica-filled polypropylene

Titanate coupling agents have been used for the surface modification of mica to improve the viscoelastic behaviour of mica-filled polypropylene. Four titanate coupling agents, neoalkoxy tri(dioctylpyrophosphato) titanate (CA1), neoalkoxy trineodecanoyl titanate (CA2), bisacetylacetonatodistearato titanate (CA3), and bisacetylacetonatodipalmitato titanate (CA4), were used in the present investigation. Mica powder (10 μm, particle size) was coated with these coupling agents in varying concentrations (0.5-10% based on the weight of the filler), and then blended with stabilised polypropylene powder of 10 melt flow index (MFI). The mica-filled (10-50 wt%) polypropylene samples were extruded and used in the granular form for studying the viscoelastic behaviour. The melt viscosity of titanate coated mica-PP samples decreases irrespective of the nature of the coupling agent used. The activation energy of melt rheology is independent of the mica content. The die swell increases with the use of titanate coupling agent. Compatibility of mica and polypropylene has also been studied with the help of a scanning electron microscope.     

钛酸钾催化DMC酯交换反应合成碳酸二异辛酯的研究

研究了碳酸二甲酯（DMC）与异辛醇（EHOH）酯交换合成碳酸二异辛酯（DEHC）的反应,对几种钾盐的催化性能比较,发现K2TiO3具有较好的催化活性和选择性。实验结果表明,K2TiO3为催化剂时,最佳反应条件为：反应温度140 ℃,反应时间2 h,n(DMC)∶n(EHOH)=1∶3,催化剂用量为原料总质量的1%,DMC转化率为72.1%,DEHC收率为57.6%,DEHC选择性为79.2%。     

钛酸钾晶须在工程塑料中应用的研究

钛酸钾晶须长度为40～80μm,加入到塑料中制成的复合材料,其耐磨损、耐高温、机械性能好,具有良好的化学稳定性,使用寿命可大大延长。     

Heterogeneity and anisotropy of injection‐molded discs of polypropylene and polypropylene composites

The anisotropy and heterogeneity of injection‐molded discs of polypropylene, talc‐filled polypropylene composites, and silane‐treated talc‐filled polypropylene composites are studied by means of dynamic mechanical analysis and thermomechanical analysis. The aims of this work are to discover the relationships between the structure of the composites, their anisotropic properties, and the heterogeneity of the molded discs. The experimental results show that although the discs are almost homogeneous, they present a high degree of anisotropy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1275–1283, 2000     

氯化聚丙烯的乳化

对氯化聚丙烯的乳化作了初步探索。实验表明,用十二烷基硫酸钠和磺化蓖麻油作乳化剂,可以把氯化聚丙烯制咸水性乳液涂料。从粘附力和拉伸剪切强度测定结果可以看出,用水性氯化聚丙烯代替溶剂型氯化聚丙烯是可行的。     

Deacetylation of β‐chitin. II. Factorial experimental design

A 2³‐factorial experimental design has been used to study the main, two‐factor‐interaction, and three‐factor‐interaction effects of the NaOH concentration (X₁), deacetylation time (X₂), and deacetylation temperature (X₃) on the degree of deacetylation (DD) of deacetylated products prepared from β‐chitin. Because the DD values of deacetylated products increase as X₁, X₂, or X₃ increases, the main, two‐factor‐interaction, and three‐factor‐interaction effects for these three deacetylation conditions are positive. The sequence of the main effects on the DD values of deacetylated products is X₃ < X₂ < X₁. The sequence of the two‐factor‐interaction effects on the DD values of deacetylated products is X₂ versus X₃ < X₁ versus X₃ < X₁ versus X₂. The prediction equation is ? = 42.4 + 13.9X₁ + 9.4X₂ + 8.4X₃ + 5.8X₁X₂ + 4.9X₁X₃ + 3.7X₂X₃ + 2.6X₁X₂X₃ (where ? is the predicted response) © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2423–2428, 2004     

接枝共聚改性氯化聚丙烯乳液的研究

以丙烯酸酯单体作为接枝共聚单体,合成了无芳烃低VOC的CPP(氯化聚丙烯)乳液。以接枝率和耐水性作为衡量指标,采用单因素试验法优选出制备CPP乳液的最佳工艺条件。结果表明:当反应温度为95℃、反应时间为3.5 h、w(总引发剂)=1.0%(其中10%引发剂在滴加单体以前加入,并且间隔时间为10 min)、w(丙烯酸酯单体)=30%和w(丙烯酸)=5%时,相应CPP乳液的综合性能相对较好,并且其对聚丙烯(PP)基材的附着力相对最好。