CaCO_3/聚丙烯共混制备多孔聚丙烯纤维的研究

以CaCO3为成孔剂,与聚丙烯相混合制得多孔纤维。研究了CaCO3/聚丙烯共混物的流动性和密度,考察了CaCO3/聚丙烯共混纤维的力学性能、吸湿性能与表面形态。结果表明:CaCO3/聚丙烯共混物为切力变稀流体,流体表观黏度随着CaCO3含量的增加而减小,减小程度与CaCO3含量有关。CaCO3含量增加,共混物密度增大,共混纤维的力学性能下降,回潮率增大。经酸处理后共混纤维表面存在多孔结构。     

尼龙6与低密度聚乙烯和乙烯—醋酸乙烯酯共聚物的共混物

本文研究了尼龙6(N_6)/低密度聚乙烯(LDPE)共混物的热和力学性能以乙烯—醋酸酯共聚物作为第三组分对N6/LDPE共混物性能的影响。共混物的拉伸强度和拉伸模量随LDPE含量的增加而降低,而断裂伸长率随LDPE含量的增加而增加。LDPE的加入可以改进N6均聚物的流动性能。热分析结果表明,共聚物中LDPE含量在10％以内,N6的熔化热和结晶度基本不变。LDPE在N6/LDPE/EVA其混物中比在N6/LDPE共混物中有较低的熔化热,但其熔点在实验误差范围内保持不变。     

CPVC/PVC共混物性能研究

采用CPVC与PVC共混,研究共混物的力学性能和耐热性,并考察纳米CaCO3对其性能的影响.结果表明:随着CPVC含量的增加,共混物的拉伸强度、弯曲强度和耐热性能都有明显的提高,冲击强度则先增后减;随着CaCO3含量增加,共混物的冲击强度和耐热性能都逐渐提高,但拉伸强度和弯曲强度则呈下降趋势.     

CaCO3改性ABS/PVC/PE-C共混体系的研究

研究了不同种类的CaCO3对ABS/PVC/PE-C共混体系力学性能的影响以及活性CaCO3对ABS/PVC/PE-C共混体系相容性、拉伸强度、弯曲强度、冲击强度、硬度、耐热性能和耐水性能的影响。结果表明：ABS/PVC/PE-C共混体系为部分相容体系,加入活性CaCO3后共混体系的相容性略有提高,在ABS/PVC/PE-C（70/30/10）共混体系中加入活性CaCO3后,体系的弯曲强度和冲击z强度先随CaCO3含量的增大而升高,当CaCO3含量达到一定值后,又随其增大而降低,CaCO3含量在10%-15%时可获得最好的综合力学性能。同时活性CaCO3的加入使ABS/PVC/PE-C共混体系的吸水率有所降低,维卡软化温度和硬度则随着CaCO3含量的增加而有所升高。     

CaCO_3对SBS/PS共混体系的增强增韧研究

采用熔融共混法制备了丁苯热塑性弹性体(SBS)/聚苯乙烯(PS)共混材料,研究了CaCO3对SBS/PS共混物拉伸性能、弯曲性能、冲击性能和耐热性能的影响。结果表明:CaCO3用量的增加,对SBS/PS共混物拉伸强度的影响不大,而断裂应变有所提高;SBS/PS共混物弯曲模量、弯曲强度、定挠应力和弯曲破坏应力呈现先下降后上升的趋势,且均比未添加CaCO3时有较大幅度提升;SBS/PS共混物的冲击强度和维卡软化温度也随着CaCO3用量的增加而提高。     

交联剂和助交联剂对ABS/PP/CaCO3反应性共混的影响

为提高ABS/PP/CaCO3复合材料相容性,采用转矩流变仪观察了ABS/PP/CaCO3三元复合物反应性共混后的扭矩,考察了不同的助交联剂蓖麻油(CO)、异氰脲酸三烯丙酯(TAIC)、松香酯(JS-1)、二甲基丙烯酸乙二醇酯(GD)以及交联剂过氧化二异丙苯(DCP)的用量对共混物的影响.研究结果表明,在交联剂DCP为0.2%(wt)时,助交联剂GD比CO、TAIC、JS-1对ABS/PP/CaCO3体系有更好反应共混效果;反应共混超过2.5 min后,随DCP量增加,复合材料将发生严重的降解.用毛细管流变仪研究了复合材料的流变特性,结果显示用DCP/GD交联体系反应共混的ABS/PP/CaCO3复合材料的剪切黏度,随温度、剪切速率的增加而下降,比较同一剪切速率下的非牛顿指数,说明其流动性能优于纯ABS.力学性能测试数据说明,用DCP/GD交联的ABS/PP/CaCO3复合材料比未交联的有较高的弯曲强度和模量.电镜观察揭示了用DCP/GD动态交联的ABS/PP/CaCO3复合材料有更好的界面相容.     

用基本断裂功方法表征聚合物基纳米复合材料的韧性

将基本断裂功(EWF)方法成功地拓展应用于表征聚丙烯(PP)/纳米CaCO3二元共混体系、PP/乙烯-1-辛烯共聚物(POE)二元共混体系以及PP/POE/纳米CaCO3三元共混体系的冲击韧性.在PP/纳米CaCO3共混体系中,比基本断裂功(ωe)随着纳米CaCO3的加入而增加.在PP/POE共混体系中,ωe随POE的加入先减至最小值,而后大幅增加.在PP/POE/纳米CaCO3三元共混体系中,纳米CaCO3使ωe有进一步提高.并对不同体系共混物的不同βωp揭示的断裂过程塑性形变机理进行了初步探讨.     

化学交联PP/LDPE共混材料的熔体强度及发泡性能

通过化学交联提高聚丙烯/低密度聚乙烯(PP/LDPE)共混物的熔体强度,并对交联PP/LDPE共混物的发泡性能进行了研究.结果表明:交联PP/LDPE共混物熔体在拉伸过程中出现明显的应变硬化现象,熔体强度明显提高;采用交联PP/LDPE共混物可制得泡孔均匀、性能良好的闭孔泡沫材料;随着LDPE含量的增加,交联PP/LDPE共混物的凝胶含量逐渐增加,熔体流动速率(MFR)减小;随着发泡剂用量的增加,交联PP/LDPE共混物泡沫的密度逐渐减小,泡孔孔径略有增大;随着泡沫密度的减小,泡沫材料的拉伸强度、压缩强度及压缩永久变形逐渐减小,拉伸断裂伸长率基本不变.     

纳米CaCO3填充ABS/PP合金复合物研究

通过熔融共混使纳米CaCO3粒子周围包覆上一层TPE橡胶,制备出纳米CaCO3母料,用其与PP、ABS共混复合制备出ABS/PP合金纳米填料复合物.该复合材料力学性能及熔体流动性能测试结果表明,纳米CaCO3含量在试验用量范围内,ABS纳米CaCO3复合物的拉伸强度随填料含量的增加而增加,当母料含量为17%,母料中纳米CaCO3填料含量为60%左右时有较佳的冲击性能;ABS/PP纳米CaCO3复合物在PP含量9%～10%时有最好的拉伸强度和冲击强度;纳米CaCO3填料含量对复合物的拉伸强度影响不大,随其用量增加对冲击强度有明显的提高;熔体流动性能在PP含量10%左右时达最大,但随填料含量增加而下降.     

不同处理方法对淀粉/LDPE共混物性能的影响

通过对淀粉添加偶联剂的表面处理、添加增容剂、熔融接枝和化学交联反应的4种方法处理淀粉/LDPE共混物,采用X光衍射仪、DSC热分析仪和红外光谱分析仪对改性后的体系进行全面分析。并结合不同处理方法对共混物力学等性能的影响进行分析,认为对淀粉添加偶联剂的表面处理、添加增容剂和交联反应均未能明显改变淀粉和聚乙烯两个结晶相混合的状态,而采用丙烯酸单体进行接枝的方法可以降低两相的结晶度,并能较好地提高淀粉和LDPE的相容性,显著提高淀粉/LDPE共混物的力学性能和塑化性能。     

Effect of Morphology on the Biodegradation of Thermoplastic Starch in LDPE/TPS Blends

In this study, thermoplastic starch (TPS) was mixed with low density polyethylene with different melt flow indexes in a one-step extrusion process to produce LDPE/TPS blends varied from 32% to 62% by weight of TPS. The influence of starch content and LDPE viscosity on morphology, biodegradation and tensile properties of LDPE/TPS blends were evaluated. Starch continuity and biodegradability were studied by hydrolytic, enzymatic and bacterial degradation. The LDPE viscosity had a considerable effect on the morphology and the connectivity of the starch particles. Evaluation of hydrolytic extraction showed that blends having TPS content above 50 wt% possessed a full connectivity. Studies of biodegradation indicated that the bacterial attack on starch resulted in weight loss of TPS of 92%, 39% and 22%, for PE1/TPS having 62% and 32% TPS, and PE2/TPS (31% TPS), respectively. Comparatively, the weight loss was more significant at 100%, 66% and 31% by hydrolytic extraction. Differences between these two techniques were discussed in terms of the accessibility of starch domains to microorganisms. Tensile properties (ε_b and E) decreased with increasing exposure time to activated sludge. Changes in tensile properties were highly dependent on the biodegradation rate. PE1/TPS blends having 32% starch remained ductile after 45 days of exposure to bacterial attack.     

Morphology and rheological properties of compatibilized low‐density polyethylene/linear low‐density polyethylene/thermoplastic starch blends

Morphology and rheological properties of low‐density polyethylene/linear low‐density polyethylene/thermoplastic starch (LDPE/LLDPE/TPS) blends are experimentally investigated and theoretically analyzed using rheological models. Blending of LDPE/LLDPE (70/30 wt/wt) with 5–20 wt % of TPS and 3 wt % of PE‐grafted maleic anhydride (PE‐g‐MA) as a compatibilizer is performed in a twin‐screw extruder. Scanning electron micrographs show a fairly good dispersion of TPS in PE matrices in the presence of PE‐g‐MA. However, as the TPS content increases, the starch particle size increases. X‐ray diffraction patterns exhibit that with increase in TPS content, the intensity of the crystallization peaks slightly decreases and consequently crystal sizes of the blends decrease. The rheological analyses indicate that TPS can increase the elasticity and viscosity of the blends. With increasing the amount of TPS, starch particles interactions intensify and as a result the blend interface become weaker which are confirmed by relaxation time spectra and the prediction results of emulsion Palierne and Gramespacher‐Meissner models. It is demonstrated that there is a better agreement between experimental rheological data and Coran model than the emulsion models. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44719.     

HDPE／NBR共混物流变性能研究

通过熔融共混法制备了HDPE／NBR共混物,用毛细管流变仪研究了其流变特性,此共混物属于假塑性流体,表观粘度随剪切速率和温度的升高而降低,随NBR和增容剂含量的降低而降低。     

Morphology,thermomechanical properties,and biodegradability of low density polyethylene/starch blends

The biodegradability of low density polyethylene (LDPE)/starch and LDPE/starch/starch acetate (STAc) blends was tested and observed to be dependent on STAc content. The binary and ternary blends containing up to a maximum concentration of 30% starch were examined for their thermal, mechanical, and morphological properties. The blends with no STAc or 2.5% STAc show almost no adherence of two phases. With 10% STAc, dispersion of starch was observed to increase with some adherence to LDPE. Tensile strength, elongation at break, and Izod impact strength of the blends decreased with increased starch content. However, incorporation of STAc along with starch improved all these properties, particularly elongation at break and toughness. The melt flow index was also improved on partial substitution of starch by STAc. Maximum biodegradability was observed for the blends containing 30% (starch + STAc). Cell growth was observed to increase with increasing concentration of (starch + STAc) in the blends. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2791–2802, 1999     

低密度聚乙烯／聚二苯胺磷腈复合材料的相容性

采用先开环聚合后取代的方法合成了聚二苯胺磷腈（PDAP）,将PDAP与低密度聚乙烯（LDPE）熔融共混制得PDAP／LDPE复合材料,并对这种复合材料的热性能和流变行为进行了表征,结果表明,LDPE／PDAP共混物具有比LDPE更高的热稳定性,HAAKE共混实验表明,随着PDAP组分的增加,加工粘度下降,动态流变实验说明,PDAP／LDPE共混物是一种典型的假塑性流体,PDAP组分有利于增加共混物的加工弹性,降低体系的表观粘度;热重分析,共混扭矩分析以及动态流变实验都证明两个组分发生了相容。     

Rheological and Mechanical Properties of LDPE/HDPE Blends

Melt rheology and mechanical properties of binary blend of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) have been investigated. Four different wt fractions of blends containing LDPE/HDPE (20/80, 40/60, 60/40, and 80/20) were prepared. Cole-Cole plots [storage melt viscosity (η′) vs. loss melt viscosity (η″)] and relation between storage melt viscosity (η′) with frequency (ω) and blend composition were constructed. Miscibility of blends was established from rheological data. Impact strength of the blends increased with increasing LDPE concentration, whereas tensile strength shows the opposite trends. Percentages of the crystallinity of the blends were calculated by both the differential scanning calorimetry and wide-angle X-ray scattering methods, which show that the percentage of crystallinity decreased with increasing LDPE concentration, but the rate of crystallization of HDPE phase was unaffected.     

Tensile properties,morphology, and biodegradability of blends of starch with various thermoplastics

In the present study, blends of starch with different thermoplastics were prepared by a melt blending technique. The tensile properties and morphology of the blends were measured. It was found that with increasing starch content in starch/ionomer blends, the tensile strength and modulus increase. But for starch/low‐density polyethylene (LDPE) and starch/aliphatic polyester (APES) blends, tensile strength and modulus decrease with increasing the starch loading. Elongation at break values of all the blend systems decrease with increasing starch loading. The scanning electron micrographs (SEM) support the findings of tensile properties. Better homogeneity is observed in starch/ionomer systems compared with that in starch/APES and starch/LDPE systems. Up to 50% starch content, the starch/ionomer blends appear as a single phase. The extent of phase interactions of starch/APES system lies in between the starch/LDPE and starch/ionomer systems. From the biodegradability studies of the blends it was found that, although the pure LDPE and ionomer are not biodegradable, the starch/LDPE and starch/ionomer blends are biodegradable with an appreciable rate. The rate of biodegradation of the starch/APES is very high as both the components are biodegradable. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2907–2915, 2002     

Radiation‐assisted morphology modification of LDPE/TPS blends: A study on starch degradation‐processing‐morphology correlation

Potato starch was radiolytically degraded to different extents by irradiating with Co‐60 gamma radiation in wide dose range. The degraded starch was plasticized using glycerol and water to obtain radiation processed thermoplastic starch (RTPS). Blends of different RTPS and low density polyethylene (LDPE) were prepared by internal melt mixing. Characterization of blends using differential scanning calorimetry, thermogravimetric analysis, X‐ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscope, melt flow, contact angle, and soil burial studies indicated changes in the blend morphology and biodegradation behavior with the increase in the dose imparted to the starch fraction. Molecular weight of starch decreased substantially in the dose range of the study. The melt viscosity of LDPE/RTPS blend decreased whereas crystallinity of LDPE phase increased with the incorporation of RTPS. No significant change in the carbonyl index and thermal stability of the blends was observed in the dose range studied; therefore, the observed changes in the physical and thermal properties of the blends were attributed primarily to the kinetic factors affecting crystallization and time‐dependent phase separation process. Biodegradability of blends varied with the radiation dose imparted to starch component of blend, suggesting better encapsulation of RTPS by LDPE chains. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Elongational rheology of LLDPE / LDPE blends

The objective of this study is to investigate the effect of low density polyethylene (LDPE) content in linear low density polyethylene (LLDPE) on the crystallinity and strain hardening of LDPE / LLDPE blends. Three different linear low density polyethylenes (LL‐1, LL‐2 and LL‐3) and low density polyethylenes (LD‐1, LD‐2 and LD‐3) were investigated. Eight blends of LL‐1 with 10, 20, 30 and 70 wt % of LD‐1 and LD‐3, respectively, were prepared using a single screw extruder. The elongational behavior of the blends and their constituents were measured at 150°C using an RME rheometer. For the blends of LL‐1 with LD‐1, the low shear rate viscosity indicated a synergistic effect over the whole range of concentrations, whereas for the blends of LL‐1 with LD‐3, a different behavior was observed. For the elongational viscosity behavior, no significant differences were observed for the strain hardening of the 10–30% LDPE blends. Thermal analysis indicated that at concentrations up to 20%, LDPE does not significantly affect the melting and crystallization temperatures of LLDPE blends. In conclusion, the crystallinity and rheological results indicate that 10–20% LDPE is sufficient to provide improved strain hardening in LLDPE. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3070–3077, 2003     

Effects of glycerol and PE‐g‐MA on morphology,thermal and tensile properties of LDPE and rice starch blends

The effects of glycerol and polyethylene‐grafted maleic anhydride (PE‐g‐MA) on the morphology, thermal properties, and tensile properties of low‐density polyethylene (LDPE) and rice starch blends were studied by scanning electron microscopy (SEM), differential scanning calorimetry, and the Instron Universal Testing Machine, respectively. Blends of LDPE/rice starch, LDPE/rice starch/glycerol, and LDPE/rice starch/glycerol/PE‐g‐MA with different starch contents were prepared by using a laboratory scale twin‐screw extruder. The distribution of rice starch in LDPE matrix became homogenous after the addition of glycerol. The interfacial adhesion between rice starch and LDPE was improved by the addition of PE‐g‐MA as demonstrated by SEM. The crystallization temperatures of LDPE/rice starch/glycerol blends and LDPE/rice starch/glycerol/PE‐g‐MA blends were similar to that of pure LDPE but higher than that of LDPE/rice starch blends. Both the tensile strength and the elongation at break followed the order of rice starch/LDPE/glycerol/PE‐g‐MA blends > rice starch/LDPE/glycerol > LDPE/rice starch blends. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 344–350, 2004