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Totally found 4135 items.

  • [会议] A Highly Active and Selective β-Nucleating Agent for Isotactic Polypropylene and Crystal Transfer at Largely Different Supercooling
    A highly active and selective novel β-nucleating agent(Adi30) for isotactic polypropylene(i PP) was found and its effects on the mechanical properties, the content of β-crystal, and crystallization behavior and non-isothermal crystallization kinetics of i PP were investigated, respectively. The results show that the impact strength and crystallization peak temperature of nucleated i PP were greatly increased, while the spherulite size of nucleated i PP was dramatically decreased than that of neat i PP. The content of β-form of nucleated i PP(kβ value) can reach 97.3% with 0.1 wt% Adi30, which showed Adi30 is a highly active and selective β-nucleating agent for i PP. Fast scanning chip calorimetry(FSC) was first used to investigate crystal transfer of β-nucleated i PP at largely supercooling. An amazing phase transfer in β-nucleated i PP at largely supercooling was found. With the increase of supercooling from 60 to12000℃/min, the β-crystal gradually transfer to α-crystal in i PP/Adi30. Non-isothermal kinetics of neat iPP and nucleated i PP was studied and the results indicated that the addition of Adi30 change the type of nucleation but do not change growth geometries of iPP.
    关键词: 聚丙烯;β晶型成核剂;结晶;晶型转变
  • [会议] Improvement of polypropylene (PP)-modified bitumen through lignin addition
    Polypropylene (PP) is usually added to bitumen to improve its mechanical properties, however, both of them have different chemical properties. To achieve best mechanical properties of the mixture, coupling agent such as lignin is importantly required. Lignin is an amorphous biopolymer, has bipolar characteristic due to its distinct chemical function which has carbonyl, carboxyl, hydroxyl and phenol chemical function. Otherwise, bitumen and PP have polar and non-polar characteristic, respectively. In the previous research, it is found that lignin is potential to be used as coupling agent. In order to confirm the potential of lignin as a coupling agent, there are various compounds of lignin on PP-bitumen mixtures used in this research. This experiment consists of several stages, ranging from sample preparation, characterization of raw materials, mixing, and characterization of the PP-Modified Bitumen. This experiment used hot melt mixing to mix lignin, PP, and bitumen. The result of this experimental was analyzed by using FTIR and FESEM. The addition of lignin make Polymer Modified Bitumen (PMB) getting better mixing and increase mechanical properties. Furthermore, FESEM characterization indicated that the addition of lignin gave better mixing of PP-Bitumen. FTIR showed a new chemical structure due to the addition of lignin. From this experiment, the addition of lignin can improve mixing between PP and Bitumen. So, we can use lignin as coupling agent.
    关键词: Lignin (major);Bituminous materials;Characterization;Coupling agents;Mechanical properties;Mixing;Mixtures;Polymers;Polypropylenes
  • [会议] Thermal properties of polypropylene and polyethylene blends (PP/LDPE)
    The paper investigates the thermal properties of polymer blends of polypropylene and low-density polyethylene. Investigations of polypropylene thermal properties are important from a scientific point of view as they explain the polymer performance at elevated temperatures and define the choice of a suitable material according to the application, as well as predict the structure and methods of creating new materials with required properties [1,2].
    关键词: -
  • [会议] Synthesis and Characterisation of Carbon Nanomaterials (CNMs) Using Polypropylene(PP) Waste as Carbon Precursor: Effect of Reactor Temperature
    Fully utilisation of urban wastes such as polymer waste is considered as promising step to save the environment besides contributing to the production of Carbon Nanomaterials (CNMs) and their insight in mechanism involved. In this work, CNMs were successfully synthesised using polypropylene (PP) waste as carbon precursor via Chemical Vapour Deposition (CVD). Ferrocene was used as metal catalyst whereas argon was used as purging gas. The CVD were operated at various reactor temperatures to assess the possibility of CNMs growth at 600℃, 700℃, 800℃, 900℃, and 1000℃ The reaction time and argon flow rate were fixed at 90 minutes and 85 ml/min, respectively. The production of CNMs started at reactor temperature of 700℃ and increased steadily from 0.0178 g to 0.2950 g with elevated temperature up to 1000℃ The diameter distribution of synthesised-CNMs reduced with the increased of reactor temperature. The XRD patterns revealed a sharp diffraction peak at around 26° (002) and broad diffraction peak at around 44° (111) which was proven to be Carbon Nanotubes (CNTs). Reactor temperature of 800℃ considered as the best temperature to synthesis small diameter of CNMs in high quantity.
    关键词: Carbon Nanomaterials (CNMs);Polypropylene (PP);Chemical Vapour Deposition (CVD)
  • [会议] Effects of PP modification and processing time on fiber/matrix interfacial strength for carbon fiber reinforced polypropylene
    Polypropylene (PP) resin is expected to be used as the matrix of Carbon Fiber Reinforced Thermoplastics (CFRTP) because of its superior properties such as low cost and good processability. However, PP has poor interfacial adhesion with carbon fibers because PP is a non-polar polymer. Therefore, it is necessary to improve its interfacial properties in order to use PP as the matrix of CFRTP. The interfacial properties of CF/PP composites are reported to be improved by introducing a chemical reaction using a modified PP matrix. To enhance this chemical reaction which is time dependent, the processing time is likely to affect the interfacial strength. In this study, to evaluate the influence of PP modification and processing time on the fiber/matrix interfacial shear strength of CF/PP model composites, single fiber pull-out tests were carried out on CF/PP composites produced at different processing times using unmodified PP and various modified PP. The interfacial shear strengths of CF/PP composites using modified PP were higher than those of CF/PP composites using unmodified PP. Long processing time improved the interfacial strength regardless of PP modification and the highly polar modified PP had the highest improve ratio of the interfacial strength.
    关键词: carbon fiber;polypropylene;PP modification;interfacial properties;processing time.
  • [会议] Effects of PP modification and processing time on fiber/matrix interfacial strength for carbon fiber reinforced polypropylene
    Polypropylene (PP) resin is expected to be used as the matrix of Carbon Fiber Reinforced Thermoplastics (CFRTP) because of its superior properties such as low cost and good processability. However, PP has poor interfacial adhesion with carbon fibers because PP is a non-polar polymer. Therefore, it is necessary to improve its interfacial properties in order to use PP as the matrix of CFRTP. The interfacial properties of CF/PP composites are reported to be improved by introducing a chemical reaction using a modified PP matrix. To enhance this chemical reaction which is time dependent, the processing time is likely to affect the interfacial strength. In this study, to evaluate the influence of PP modification and processing time on the fiber/matrix interfacial shear strength of CF/PP model composites, single fiber pull-out tests were carried out on CF/PP composites produced at different processing times using unmodified PP and various modified PP. The interfacial shear strengths of CF/PP composites using modified PP were higher than those of CF/PP composites using unmodified PP. Long processing time improved the interfacial strength regardless of PP modification and the highly polar modified PP had the highest improve ratio of the interfacial strength.
    关键词: carbon fiber;polypropylene;PP modification;interfacial properties;processing time.
  • [会议] 22.9 kV Polypropylene Insulated Power Cable with Soft Polypropylene
    Polypropylene(PP) insulated power cable has developed the field of MV and HV extruded cables in Europe. In the present study, for cable application of impact PP, the effect of ethylene propylene rubber(EPR) design on morphology and mechanical properties was investigated. We developed 22.9 kV PP insulated power cable with soft polypropylene which is impact PPs. Impact PPs having various EPR compositions were prepared using a high activity Ziegler-Natta catalyst. The impact PP suitable for insulation applications was commercially polymerized and its mechanical and thermal properties were evaluated. EPR composition and morphology were characterized by scanning electron microscopy(SEM). The glass transition temperature related to impact strength at low temperature was examined using dynamic mechanical analysis(DMA). Tensile strength and elongation of the impact PP before and after thermal aging were good. The impact PP in this study has higher thermal resistance than XLPE and shows higher softness and low temperature resistance than general designed PP. The 22.9 kV PP insulated power cable with the impact PPs was prepared by extrusion process. The thermal, mechanical and electrical properties for the cable were investigated. Pressure test of the PP insulation was conducted at high temperature at 130 ℃ for 6 hours. Deformation for the thickness of the insulation under load was much smaller than XLPE because thermal stability is better than XLPE. The bending test results showed that the flexibility of the cable was good enough for cable application. Electrical properties of the PP insulated power cable such as AC withstand voltage, AC breakdown voltage, impulse voltage in hot condition and dissipation factor(tanδ) were similar to XLPE cable. As the results, we successfully developed the 22.9 kV PP insulated power cable using a new PP insulation which has environmental friendliness, good thermal, mechanical and electrical properties. It is expected that 22.9 kV PP insulated power cable is available to the high temperature power cable.
    关键词: Power cable;Eco-friendly cable;Polypropylene insulation
  • [会议] EFFECT OF POLYPROPYLENE-GRAFTED-NANOSILICA ON THE RHEOLOGICAL AND CRYSTALLIZATION PROPERTIES OF ISOTACTIC POLYPROPYLENE
    Grafting polymer to nanoparticles is a promising strategy to improve the compatibility and interfacial connections at once [1]. While the reports on the polypropylene (PP)-grafted nanofillers are limited due to the difficulty in synthesis and low grafting efficiency [2, 3]. In this work, long chain polypropylene-grafted SiO2 (PP-g-SiO2) nanoparticles were prepared through reactive melt blending of maleic-anhydride-grafted polypropylene (PP-MAH) and co-condensed amino-functionalized silica (SN-NH2). The amount of grafted PP was high up to 80.8 wt%. The shear and extension rheology studies of isotactic PP (iPP)/PP-g-SiO2
    关键词: SiO;EFFECT OF POLYPROPYLENE-GRAFTED-NANOSILICA ON THE RHEOLOGICAL AND CRYSTALLIZATION PROPERTIES OF ISOTACTIC POLYPROPYLENE
  • [会议] Tensile and morphological studies of polypropylene/ empty fruit bunch composite: Effect of maleic anhydride-grafted polypropylene
    The effect of maleic anhydride-grafted polypropylene (PPMAH) as compatibilizer on the tensileand morphological properties of polypropylene (PP)/ empty fruit bunch (EFB) composite were investigated. The composite was melt mixed using a heated two roll mill at 180 °C with speed of 15 rpm for seven different EFB filler loadings (70/30, 75/25, 80/20, 85/15, 90/20, 95/5 and 100/0 wt%). From the analysis, tensile strength and elongation at break decreased with increasing EFB filler loading. However, it is interesting to observe that the addition of PPMAH has resulted in5 to 10 % better tensile strengthcompareto without PPMAHcompatibilizer. The morphological studies from scanning electron microscopy (SEM) of tensile fracture surfaces showed thatPPMAH compatibilizercomposites also indicates improved dispersion and adhesion of EFB fibre on the PP matrix. Keywords. Maleic anhydride-grafted polypropylene, empty fruit bunch, polypropylene, tensile properties, compatibilizer
    关键词: -
  • [会议] 成核剂的层状分布对聚丙烯结晶行为及光学性能的影响研究
    聚丙烯(PP)由于其外观光泽度和透明度较差,缺少美感,在透明包装等领域受到了限制,加入成核剂减小球晶尺寸是常用的使聚丙烯高透明化的方法~([1])。本文采用微纳层共挤出技术~([2]),制备了纯PP层和PP/成核剂共混物层(PN)交替排布的多层复合材料。通过调节材料层数来调控成核剂的分布,研究其对相邻PP层结晶行为和材料光学性能的影响。差示扫描量热仪(DSC)的结果显示,低层数样品有两个结晶峰,分别对应PP层的均相成核结晶和PP/成核
    关键词: Polypropylene;microlayer coextrusion;mutilayered distribution;crystallization behavior;optical property
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