Microporous polypropylene sheets containing polymethylsilsesquioxane filler

Plasma polymerized membranes were prepared from octamethyltrisiloxane for the purpose of separation of O₂ over N₂. The obtained membrane consisted of plasma prepared polymer layer on top of a porous polyproplene substrate. The membrane polymerized under the mild plasma condition (low power input and high monomer flow rate) showed the high permeation rate. Selectivity, however, was hardly affected by the plasma conditions. The selectivity and permeation rate obtained were 2.6 and 2.5 × 10^?10 kmol/(m²·s·Pa) (=7.5×10^?4 cm³/(cm²·s·cmHg)), respectively. This high permeation rate was attributed to the use of the monomer with the long, flexible siloxane chain and the mild plasma condition. Moreover, the membranes were prepared from a series of monomers with different siloxane chain lenghts (methoxytrimethylsilane, hexamethyldisiloxane, and octamethyltrisiloxane), and from those with different alkyl chain lenghts (methoxytrimethylsilane, propoxytrimethylsilane, and hexyloxytrimethylsilane). As the siloxane chain lenghts of the starting monomers increased and the alkyl chain lengths decreased, the permeation rates of the corresponding polymers increased. The selectivities were nearly constant regardless of the difference in the starting monomer structures. The structures of the plasma prepared polymers were analyzed by XPS and IR measurements, and discussed in relation to the membrane efficiencies. © 1994 John Wiley & Sons, Inc.     

Microporous polypropylene sheets containing polymethylsilsesquioxane filler

Microporous sheets were prepared by biaxially stretching composite nonporous sheets composed of microspherical polymethylsilsesquioxane particles encased in polypropylene. The structural and physical property studies of the sheets obtained thereby show that the porosity, pore-size distribution, and the tortuosity vary with the average diameter of the encased particles as expected on the basis of theory. © 1993 John Wiley & Sons, Inc.     

Microporous polypropylene sheets containing CaCO3 filler

Biaxial stretching of polypropylene sheets containing CaCO₃ filler results in microporous sheets, that feel soft and dry. Their properties depend on filler content, particle size of the filler, and stretching degree etc. We have studied the dependency of some properties of the microporous polypropylene sheets on stretching degree. It is elucidated that mechanical properties are controllable by adjusting stretching degrees in machine and transverse directions. © 1993 John Wiley & Sons, Inc.     

Structure of microporous polypropylene sheets containing CaCO3 filler

The microporous polypropylene sheets were prepared by biaxially stretching polypropylene sheets containing CaCO₃ filler (particle size, 0.08–3.0 μm), when the CaCO₃ filler content was 59% by weight and the stretching ratio was 2.8 × 1.8. The microstructure of the sheets were investigated in relation to the CaCO₃ particle size by a N₂ gas permeation method. (1) Effective porosity increases with decreasing mean particle size of filler. (2) The tortuosity factor of the pore is in the range of 25–40 and becomes relatively smaller with decreasing mean particle size of filler. (3) The equivalent pore size becomes relatively smaller with decreasing mean particle size of filler.     

Microporous polypropylene fibers containing poly(methylsilsesquioxane) filler

Microporous polypropylene fibers were prepared by stretching polypropylene fibers containing poly(methylsilsesquioxane) filler. The properties of the resultant fibers are controllable by adjusting the filler content and stretching degree. The resultant fibers have a fine texture of polypropylene fibrils, in which the filler particles are dispersed. Some properties were investigated: tensile strength, elongation, Young's modulus, porosity, pore size, and specific surface area. © 1996 John Wiley & Sons, Inc.     

Microporous polypropylene sheets containing CaCO3 filler: Effects of stretching ratio and removing CaCO3 filler

Microporous polypropylene sheets are prepared by biaxially stretching polypropylene sheets containing CaCO₃ filler. Here, the stretching ratio is one of the most important factors in the preparative process, and removing the CaCO₃ filler also affects the sheet properties. Their effects were studied in relation to the properties and the structure of the microporous polypropylene sheets. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1543–1553, 1998     

Morphology prediction of ternary polypropylene composites containing elastomer and calcium carbonate nanoparticles filler

In this work, the morphology was studied in ternary composites of polypropylene (PP) with nanosized calcium carbonate (nano‐CaCO₃) fillers and elastomer inclusions and the thermodynamic consideration was used to analyze the formation of phase structure of the composites. The wetting coefficient (ω_a), interfacial tension (γ_AB), and work of adhesion (W_AB) were calculated to predict dispersion state of nano‐CaCO₃ fillers. A comparison of the prediction and SEM analysis was given. The results show that three types of phase structures were formed: an encapsulation of the filler by elastomer, a separate dispersion of the filler and elastomer, and a particular structure of the filler at the PP/elastomer interface. The predictions by ω_a were all successfully supported‐up by SEM analysis and the predictions by W_AB were however trustless. Both γ_AB and W_AB can predict a separate dispersion or an encapsulation phase structure, but they were not available for the particular structure of the filler at the PP/elastomer interface. ω_a was competent and favored for the prediction of all three types of morphology among the three parameters. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1578–1584, 2007     

Preparation of microporous polypropylene sheets containing CaCO3 filler: Effect of draft ratio

Microporous polypropylene sheets were prepared as follows. First, polypropylene pellet-containing CaCO₃ filler was extruded to prepare base sheets, which were then biaxially stretched. The draft effect at the extrusion process was studied in relation to some properties of the resultant microporous polypropylene sheets. © 1996 John Wiley & Sons, Inc.     

The microstructural and mechanical properties of geopolymer composites containing glass microfibres

This paper presents the effects of microfibre contents on mechanical properties of fly ash-based geopolymer matrices containing glass microfibres at 0, 1, 2 and 3 mass%. The influence of glass microfibres on the fracture toughness, compressive strength, Young's modulus and hardness of geopolymer composites are reported, as are the microstructural properties investigated using scanning electron microscopy. Results show that the addition of 2 mass% glass microfibres was optimal, exhibiting the highest levels of fracture toughness, compressive strength, Young's modulus and hardness. The results of the microstructural analysis indicate that the glass microfibres act as a filler for voids within the matrix, making a dense geopolymer and improving the microstructure of the binder. This leads to favourable adhesion of the composites, and produces a geopolymer composite with good mechanical properties, comparable to pure geopolymer. The failure mechanisms in glass microfibre-reinforced geopolymer composites are discussed in terms of microstructure.     

Effect of filler dispersion on polypropylene morphology

The evaluation of filler dispersion in compounding machines is an important part of their design. Calcium carbonate–filled polypropylene (PP) was used as a model compound to study filler dispersion. The evolution of dispersion was followed in a twin‐screw extruder where several types of mixing sections were evaluated. Reverse kneading blocks were found to be very efficient for breakup of agglomerates. Depending on extrusion conditions, agglomeration was observed even after the matrix was melted. To study dispersion in a single‐screw extruder, Maddock and reverse Maddock mixing elements were tried. A quantitative evaluation of the dispersion state allowed a better understanding of nucleation in the PP/CaCO₃ matrix. A significant content of the β‐phase of polypropylene was observed when the agglomerate size was relatively small. The level of shear stress was also important for the formation of the β‐phase of PP. The quantification of dispersion was mainly evaluated from micrographs of samples obtained by reflected light microscopy in conjunction with image analysis. The characterization of β‐spherulites was carried out using polarized light microscopy and scanning electron microscopy. Polym. Eng. Sci. 44:880–890, 2004. © 2004 Society of Plastics Engineers.     

Photodegradation of polypropylene containing a nucleating agent

The effect of including 0.5 wt % talc on the photodegradation behavior of polypropylene (PP) was investigated in injection-molded samples exposed to ultraviolet radiation (UV) in the laboratory for periods of up to 24 weeks. The structure of the talc-nucleated samples was characterized by X-ray diffraction and light microscopy and compared with that of nonnucleated PP, and the information was used to explain the differences in their photodegradation behavior. Measurements of the extent of chemical degradation were made by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), and they showed that there is no significant effect of a nucleating agent on the kinetics of photooxidation. PP bars containing a nucleating agent showed a larger reduction in mechanical properties with UV exposure and a partial recovery in properties after prolonged exposure was observed with both types of samples. An increase in crystallinity during UV exposure (chemicrystallization) was detected by X-ray diffraction and differential scanning calorimetry (DSC) and the dependence with exposure time was similar in nucleated and nonnucleated samples. DSC was also used to determine the melting behavior and transition temperatures of the specimens during exposure and after recrystallization from the melt. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2505–2517, 1997     

Structural-mechanical properties of corundum bodies containing a porous filler

Conclusions We studied the structural-mechanical properties of granular corundum bodies in relation to the form, amount of additives consisting of surface active substances, and the type of porous filler.It was shown that a positive influence on the forming properties of the bodies based on spherical corundum and porous corundum briquet is exerted by the incorporation of technical lignosulfonate, and moreover it is most advantageous to use 0.5% solution for the spherical corundum and 2% solution for the briquet. An addition of GKZh-11 in amounts of 0.05% is desirable only for bodies based on spherical corundum. The addition of these agents increases the plasticity of the bodies on account of reducing the internal friction between the particles, and enables us to obtain articles with good properties.Translated from Ogneupory, No. 8, pp. 10–13, August, 1987.     

Effect of zeolite filler on the thermal degradation kinetics of polypropylene

In this study, the thermal degradation behavior of polypropylene (PP) and PP–zeolite composites was investigated. Clinoptilolite, a natural zeolitic tuff, was used as the filler material in composites. The effects of both pure clinoptilolite and silver‐ion‐exchanged clinoptilolite on the thermal degradation kinetics of the PP composites was studied with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Polymer degradation was evaluated with DSC at heating rates of 5, 10, and 20°C/min from room temperature to 500°C. The silver concentration (4.36, 27.85, and 183.8 mg of Ag/g of zeolite) was the selected parameter under consideration. From the DSC curves, we observed that the heat of degradation values of the composites containing 2–6% silver‐exchanged zeolite (321–390 kJ/kg) were larger than that of the pure PP (258 kJ/kg). From the DSC results, we confirmed that the PP–zeolite composites can be used at higher temperatures than the pure PP polymer because of its higher thermal stability. The thermal decomposition activation energies of the composites were calculated with both the Kissinger and Ozawa models. The values predicted from these two equations were in close agreement. From the TGA curves, we found that zeolite addition into the PP matrix slowed the decomposition reaction; however, silver‐exchanged zeolite addition into the matrix accelerated the reaction. The higher the silver concentration was, the lower were the thermal decomposition activation energies we obtained. As a result, PP was much more susceptible to thermal decomposition in the presence of silver‐exchanged zeolite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 143–148, 2006     

Upgrading brewer's spent grain as functional filler in polypropylene matrix

Brewer's spent grain (BSG) is a by‐product of the brewing industry that contributes to a large volume of wastes. The lignocellulosic nature of this waste, together with presence of functional components such as antioxidants, represents an attractive for the composite's industry. In this work, BSG has been used as functional filler for polypropylene matrix to give an additional use to this industrial waste. Addition of BSG filler improves the overall environmental efficiency of the polypropylene matrix thus leading to high environmentally friendly materials. BSG can be loaded in the 10–40 wt% range with easy manufacturing, balanced mechanical properties, and additionally, excellent antioxidant properties are achieved with increasing BSG loading due to natural antioxidants that have not been removed during the brewing process. In particular, the onset of the thermo‐oxidative degradation of polypropylene is improved by 15–20°C for different compositions. Due to the lignocellulosic nature of BSG, water uptake is a clear drawback of PP–BSG composites but formulations containing 10‐30 wt% BSG hold the water uptake at very low values. POLYM. COMPOS., 38:40–47, 2017. © 2015 Society of Plastics Engineers     

Crystallisation of polypropylene containing nucleators

The crystallisation of polypropylene in the presence of sodium benzoate, graphite powders, Millad 3988 (1,3:2,4-bis(3,4-dimethyl-benzylidene sorbitol)) and NA-11 (sodium 2,2′-methylene bis-(4,6-di-tert-butylphenyl)phosphate) was studied. As a parameter for the effectiveness of nucleators, a free-energy parameter for the nucleation was estimated, on the basis of a theory, from the nucleation temperature during cooling at various rates. The density of actual nuclei was estimated from the radial growth rate of spherulites and the bulk growth rate, the latter obtained by the analysis of crystallisation isotherms. The dispersibility of nucleator particles calculated with reference to the mean volume of particles was various, the cluster size being ranged between unity to several hundred. The Young's modulus of films prepared from the polymer-nucleator mixtures has been found to correlate with the nucleus density without respect to the kind of nucleator.     

The influence of filler surface modification on mechanical and material properties of layered double hydroxide‐containing polypropylene composites

The processing and properties of layered double hydroxides (LDHs)‐containing polypropylene (PP) composites have been studied extensively. However, no detailed studies have reported on how stearic acid (SA)‐intercalated and SA‐coated LDHs influence the properties of melt‐processed PP/LDH composites. Here, four different types of LDHs: synthesized (cLDH1) and commercial (cLDH2) SA‐coated LDH, SA‐intercalated LDH (iLDH), and unmodified LDH (nLDH), were used to fabricate composites using a master‐batch‐dilution technique in a twin‐screw extruder. The characterization results showed that microcomposites were formed when cLDH2 and nLDH were used, whereas nanocomposites were formed when iLDH and cLDH1 were used. Strong nucleating behavior was observed for the nLDH‐, cLDH1‐, and cLDH2‐containing composites, whereas iLDH delayed the crystallization process of the PP matrix. A significant improvement in modulus, with a balance of tensile and impact strengths, was observed in the case of the cLDH1‐containing composite, whereas the nLDH‐containing composite showed good improvement in temperature‐dependent load‐bearing capacity. On the other hand, the PP/iLDH composite showed a remarkable improvement in thermal stability and a reduction in the peak‐heat‐release rate. Therefore, this study gives us an opportunity to design PP composites with desired properties by the judicious choice of LDH, which further widens the application of PP matrices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45024.     

云母对PP抗紫外光老化性能的影响

将云母填充聚丙烯(PP)进行光老化前后的力学性能比较,并采用紫外-可见光分光光度计、扫描电子显微镜等对云母及复合材料进行研究.实验表明:具有高径厚比的云母容易在塑料流体流动过程中沿着流动方向并行取向,取向后的云母不仅有利于提高PP材料的力学性能,而且云母对紫外光具有层间反射、干涉和遮蔽等效应,同时降低云母粒径,提高径厚比可有效提高改性PP的力学性能和抗紫外光老化性能.     

Effect of clinoptilolite filler on the physical and mechanical properties of polypropylene

This study aims to investigate the mechanical and physical properties of polypropylene (PP) filled by natural zeolite. For this purpose, a natural zeolite (at 1–6 wt% filler loadings) with two different particle sizes was used. Two different kinds of silane coupling agents (3‐aminopropyltriethoxysilane, GAPTES and 3‐glycidoxypropyltrimethoxysilane, GPTMS) at three different volume ratios were used to improve the zeolite compatibility with PP and to improve the mechanical properties of composites. Fillers and PP were compounded with a twin screw extruder, and the composites were moulded with injection moulding press. The samples were subjected to mechanical tests (i.e., impact and tensile tests) and physical tests (i.e., hardness, density, and melt flow index, MFI). The physical test results showed that the levels of hardness and density of both unmodified and modified zeolite‐filled PP composites were higher compared with neat PP. The MFI values of composites were decreased by increasing zeolite loading level. Composites including GAPTES modified zeolite showed improved yield strength, impact strength and stiffness compared with composites filled with unmodified zeolite particles. POLYM. COMPOS. 34:1396–1403, 2013. © 2013 Society of Plastics Engineers