Recycled content in polymer matrix composites through the use of A-glass fibers

The utility of recycled A-glass (primarily composed of soda-lime-silicate) fibers as reinforcement for structural composites has been studied. A series of plaques of unsaturated polyster composite were resin transfer molded with an A-glass continuous strand mat (CSM) and a control with E-glass CSM. The influence of fiber volume fraction on the physical and thermo-mechanical properties of the resultant composites were investigated, both before and after environmental exposure. At the maximum fiber fraction considered (nominally 29 vol%), the use of A-glass reinforcement lowered the warp direction tensile modulus from 8.6 to 7.6 GPa and strength from 139 to 100 MPa, relative to the control. Similar results were observed for both the flexural and the tensile properties, irrespective of fiber fraction and test direction (warp vs. weft), for the A-glass reinforcement. Environmental exposure was found to affect equally the properties of A-glass and E-glass fiber reinforced composites. Based upon microscopic analyses and constituent properties, the lower mechanical properties of the A-glass fibers composites have been linked to the lower properties of A-glass fibers relative to E-glass fibers. The experimental results were also used to test a micro-mechanics models for random fiber reinforced composites. Reasonable correlation was found between the experimental results and the theoretical predictions. To offset their lower mechanical properties, A-glass fibers could be used as a reinforcement in composite applications by simply increasing the fiber fraction relative to their E-glass counterpart.     

纳米CaCO3改性聚合物基复合材料研究进展

纳米碳酸钙是一种原料丰富、性能优良的无机填料,在聚合物填充改性方面,纳米碳酸钙填充聚合物基复合材料具有一些普通填充体系无法达到的优良性能。本文综述了纳米碳酸钙在聚甲基丙烯酸甲酯、聚氯乙烯和聚丙烯等材料中的改性研究进展,并对纳米填充粒子和聚合物基体的相容性及增强增韧机理进行了讨论。     

Use of polyester/glass‐fiber residues as fillers for composites

In this work, the performance of polyester (P)/glass fiber mats (G) and P/G/calcium carbonate (CaCO₃) composites was compared with that of P/G/fiberglass waste composites. The residues used were conventional P/G postconsumer light resin‐transfer‐molding parts, obtained via knife or ball milling. Composites with up to 50 wt % reinforcement were prepared by hot compression molding and characterized via physical (density and water sorption), thermal (thermogravimetry and burnout), and mechanical (impact, Barcol hardness, and tensile) testing. The results show that the simple grinding and reincorporation of the composite residues yielded new composites with generally worse characteristics than the ones with calcium carbonate. Then, the waste was sorted by removing most of the pure resin particles from it. This yielded a resin‐rich fraction, which could be better used for energy recovery and resin‐covered fibers. The use of the latter as a filler yielded composites with better overall properties than those with calcium carbonate for a controlled amount of W; thus showing potential use as a replacement for the commonly used inorganic filler, maintaining the mechanical properties, decreasing the raw material cost, and reducing the amount of composite waste discarded in the environment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

不同填料对聚氨酯及其复合材料性能的影响

研究了玻璃钢粉末、聚乙烯微粉、碳酸钙粉末、中空玻璃微珠等填料对改性聚氨酯树脂的填充效果,通过比较树脂浇铸体的拉伸和弯曲性能,说明玻璃钢粉末作为填料时树脂各项性能达到最优。结果还表明:随着玻璃钢粉末质量分数的增加,聚氨酯及其复合材料的弯曲性能表现出先增后减的趋势,其最佳填充量为10%。为此有可能将玻璃钢粉末作为填料加入树脂中实现回收利用。     

Effect of filler loading on cure time and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends

The effect of filler loading on the cure time (t₉₀) and swelling behaviour of SMR L/ENR 25 and SMR L/SBR blends has been studied. Carbon black (N330), silica (Vulcasil C) and calcium carbonate were used as fillers and the loading range was from 0 to 40 phr. Results show that for SMR L/ENR 25 blends the cure time decreases with increasing carbon black loading, whereas silica shows an increasing trend, and calcium carbonate does not show significant changes. For SMR L/SBR blends, the cure time of carbon black, silica and calcium carbonate generally decreases with increasing filler loading. The percentage swelling in toluene and ASTM oil no 3 decreases for both blends with increasing filler loading, with calcium carbonate giving the highest value, followed by silica‐ and carbon black‐filled blends. At a fixed filler loading, SMR L/ENR 25 blend shows a lower percentage swelling than SMR L/SBR blends. © 2003 Society of Chemical Industry     

Moldability and properties of phenolic/artificial zeolite composites

The purpose of this study is to improve the several properties of composites consisting of a phenolic and fly ash or artificial Zeolite such as sodium type Zeolite (Na? Ze) or calcium type Zeolite(Ca? Ze). And it also includes the improvement in the flowability of molding compounds. The molding compounds were prepared from a phenol novolac, a curing agent, and several fillers. The flowability of the compounds containing fly ash and artificial Zeolite as a filler, mentioned above, was superior to that of the compounds containing glass fiber (GF), calcium carbonate (CaCO₃), or talc as a filler. The phenolic composites were prepared from the above molding compounds by transfer molding. The phenolic composite containing Ca? Ze had most superior heat resistance, electrical insulation, and flexural strength, though in the lastly listed property it ranked next to the GF‐filled composite. The linear expansion coefficient of the composite containing Ca? Ze was as low as almost isotropic. The reasons of obtaining these excellent properties were thought to be as follows: (1) Ca? Ze could finely be dispersed in the phenolic resin to bring good impregnation. (2) The surface chemical and physical interaction between the resin and Ca? Ze was higher than that between the resin and the other fillers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Single screw extrusion compounding of particulate filled thermoplastics: State of dispersion and its influence on impact properties

The compounding of calcium carbonate filled polypropylene (PP) is discussed with reference to a single-screw extruder and variants of mixing sections. The mixing section on the screw is exchangeable, and two dispersive mixing elements, namely the Zorro and the Maddock elements, were used. The calcium carbonate was surface treated with a liquid titanate coupling agent (LICA12). The impact strength was measured by a notched Izod impact tester with specimens having a U-shaped sharp notch. The fracture toughness for the PP homopolymer and the filled composites was determined using fracture mechanics principles. The results were correlated with the state of dispersion of the calcium carbonate filler. The effects of filler concentration and surface treatment were examined as well. Correlation between state of dispersion and impact properties for calcium carbonate filled PP was obtained. We also investigated the effect of various mixing elements on the state of dispersion. The experimental results indicate that good dispersion would improve the impact properties of the polymer matrix, but only at moderate filler loading. © 1996 John Wiley & Sons, Inc.     

玻璃微珠填充聚丙烯塑料的流变性能

用CAPIROGRAPH 1B型毛细管流变仪对玻璃微珠填充的聚丙烯复合材料的流变性能进行了研究,并与不同粒径的碳酸钙、滑石粉填充的聚丙烯复合材料进行对比,证明玻璃微珠填料因其特殊的球形而体现出优越的加工流动性。     

Dynamic mechanical properties of short carbon fiber-filled styrene–isoprene–styrene block copolymer

The mechanical and dynamic mechanical properties of short carbon fiber-filled styrene–isoprene–styrene (S–I–S) block thermoplastic elastomeric composite have been studied. Brabender mixing followed by milling of the fiber–rubber compositions caused about a 30-fold decrease in the fiber aspect ratio and random fiber orientation. Although low-strain moduli increased on fiber incorporation, tensile and tear properties dropped and anisotropy in mechanical properties was not observed. Tan δ values at the T_g region decreased on filler incorporation, but at room temperature, the tan δ values increased with filler loading. The variation of storage moduli and tan δ values with frequency followed a pattern similar to the variation of these properties with filler incorporation. © 1993 John Wiley & Sons, Inc.     

Processing and Properties of Blackglas™–Nextel™ 312 (BN) Composites Incorporating Fillers

Blackglas™–Nextel™ 312 (BN) composites with and without filler materials have been processed and characterized. SiC as inactive filler, and Ti and TiB₂ as active fillers, were incorporated into the Blackglas resin, and the resulting slurries were painted on Nextel fabrics. The painted fabrics were laminated at 150°C and then pyrolyzed at 1000°C under nitrogen to fabricate ceramic–ceramic composites. The pyrolyzed composites were infiltrated with the resin up to five times to minimize the porosity and microcracks formed upon pyrolysis. Dimensional changes, open porosity, and densities of the composites were monitored throughout the process. The flexural strengths of the unfilled and filled composites after 2, 3, 4, and 5 infiltration cycles were measured by four-point bending. It was found that the addition of filler materials eliminated the delamination problem at a low number of infiltration cycles; however, the strengths of the filled composites did not reach the level of the unfilled composite. Much higher moduli were obtained for the filled composites because of the higher modulus of the filler materials relative to Blackglas.     

State of dispersion: Polypropylene filled with calcium carbonate

The influence of mixing conditions on the state of dispersion of calcium carbonate filled polypropylene composite was studied. The polymer and the filler were compounded in a twin screw extruder under various controlled processing conditions. The variables studied were the screw speed, the feed rate, the filler concentration, the barrel temperature profile and the surface treatment of the filler. The state of dispersion of calcium carbonate filled polypropylene composites was characterized using a scanning electron microscope, and was correlated to the residence time and the shearing conditions that were prevailing within the extruder. Degradation of the polymer matrix was also observed.     

THE COMPARISON PROPERTIES OF RECYCLE RUBBER POWDER,CARBON BLACK,AND CALCIUM CARBONATE FILLED NATURAL RUBBER COMPOUNDS

The effects of filler loading on the curing characteristics, swelling behavior, and mechanical properties of natural rubber compounds were studied using a conventional vulcanization system. Recycle rubber powder (RRP), carbon black (CB) (N550), and calcium carbonate (CaCO₃) were used as fillers and the loading range was from 0 to 50 phr. Results show that the scorch time, t ₂, and cure time, t ₉₀, decrease with increase in filler loading. At a similar filler loading, RRP shows shortest t ₂ and t ₉₀ followed by CB and calcium carbonate. The tensile strength, tensile modulus, and hardness increase with increase in CB loading, whereas elongation at break, resilience, and swelling properties show opposite trend. For RRP and calcium carbonate filled natural rubber compounds, the tensile strength increases up to 10 phr and starts to deteriorate at higher filler loading. The other properties such as tensile modulus, hardness, elongation at break, resilience, and swelling percentage show a small change (increase or decrease) with increase in RRP and calcium carbonate loading in natural rubber compounds. Overall results indicate that RRP can be used as a cheapener to replace calcium carbonate in natural rubber compounds where improved mechanical properties are not critical.     

An investigation on the mechanical and dynamic rheological properties of single and hybrid filler/polypropylene composites based on talc and calcium carbonate

Some results of experiments on the mechanical and rheological properties of mineral filled polypropylene were presented. Single filler and hybrid filler composites of talc and calcium carbonate (CaCO₃) were prepared in a co‐rotating twin‐screw extruder. The effect of filler type, filler content, and coupling agent on the mechanical and rheological properties of the polypropylene were studied. The coupling agent was maleic anhydride‐grafted polypropylene (PP‐g‐MA). It was found that the mechanical properties are affected by filler type, filler concentration, and the interaction between filler and matrix. The tensile strength of the composite is more affected by the talc while the impact strength is influenced mostly by CaCO₃ content. The elongation at break of PP/CaCO₃ composites was higher than that of PP/talc composites. The incorporation of coupling agent into PP/mineral filler composites increased the mechanical properties. Rheological properties indicated that the complex viscosity and storage modulus of talc filled samples were higher than those of calcium carbonate filled samples while the tan δ was lower. The rheological properties of hybrid‐filler filled sample were more affected by the talc than calcium carbonate. The PP‐g‐MA increased the complex viscosity and storage modulus of both single and hybrid composites. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

The effect of time and temperature on the mechanical behavior of epoxy composites

A crosslinked epoxy resin consisting of a 60/40 weight ratio of Epon 815 and Versamid 140 and composites of this material with glass beads, unidirectional glass fibers and air (foams) were tested in tension, compression and flexure to determine the effect of time and temperature on the elastic properties, yield properties and modes of failure. Unidirectional continuous fiber-filled samples were tested at different fiber orientation angles with respect to the stress axis. Strain rates ranged from 10^?4 to 10 in./in.-min and the temperature from ?1 to 107°C. Isotherms of tangent modulus versus strain rate were shifted to form master modulus curves. The moduli of the filled composites and the foams were predictable over the entire strain rate range. It was concluded that the time-temperature shift factors for tangent moduli and the time-temperature shift factors for stress relaxation were identical and were independent of the type and concentration of filler as well as the mode of loading. The material was found to change from a brittle-to-ductile-to-rubbery failure mode with the transition temperatures being a function of strain rate, filler content, filler type and fiber orientation angle, indicating that the transition is perhaps dependent on the state of stress. In the ductile region, an approximately linear relationship between yield stress and log strain is evident in all cases. The isotherms of yield stress versus log strain rate were shifted to form a practically linear master plot that can be used to predict the yield stress of the composites at any temperature and strain rate in the ductile region. The time-temperature shift factors for yielding were found to be independent of the type, concentration and orientation of filler and the mode of loading. Thus, the composite shift factors seem to be a property of the matrix and not dependent on the state of stress. The compressive-to-tensile yield stress ratio was practically invariant with strain rate for the unfilled matrix, while fillers and voids raised this ratio and caused it to increase with a decrease in strain rate. The yield strain of the composites is less than the unfilled matrix and is a function of fiber orientation and strain rate.     

Valorization of waste thermoset material as a filler in thermoplastic: Mechanical properties of phenolic molding compound waste‐filled PP composites

As most thermoset material, phenolic molding compound (PMC) wastes are an environmental problem. Very few recycling solutions have been proposed so far for this type of material. A mechanical recycling method to valorize these materials is proposed in this work. It relies on the use of phenolic waste as filler in thermoplastic. Such phenolic filler can increase mechanical properties (tensile, flexural) of the matrix, and be used in substitution of traditional particulate fillers such as calcium carbonate or talc. In this study, several morphological parameters influencing the final mechanical properties of a PMC‐filled polypropylene (PP) micro‐composite are studied, such as filler loading rate, particles size distribution of the filler, and interfacial adhesion between the filler and the matrix. Some structural parameters are also studied and linked with mechanical properties, such as dispersion of the filler and crystallinity of the matrix. Finally, the properties of PMC‐filled PP are compared with CaCO₃‐ and talc‐filled PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45849.     

Performance of bamboo plastic composites with hybrid bamboo and precipitated calcium carbonate fillers

The influences of hybrid bamboo and precipitated calcium carbonate (PCC) fillers in a recycled polypropylene/polyethylene matrix on the properties of bamboo plastic composites were studied. Thermogravimetric and Fourier transform infrared analyses of both thermo‐mechanically refined bamboo fiber (RBF) and ground bamboo particle (GBP) showed relatively higher holocellulose content in RBF, and more effective silane grafting on the RBF surface. The raw PCC particles contained over 95% calcium carbonate, and had an agglomerated form consisting of particles with a mean diameter of about 1.2 microns. Compounding the PCC particles with the plastic resin helped separate and disperse them in the matrix. Measured flexural strength and modulus of PCC‐only‐filled composites increased significantly from 15 to 30% PCC content levels, while the tensile and impact strength of composites decreased with the addition of PCC. For composites with hybrid bamboo and PCC fillers, tensile and flexural moduli were improved with the increase of PCC content. After silane treatment, RBF‐filled composites showed noticeably increased mechanical properties compared with those of GBP‐filled composites. For modulus values, PCC–bamboo–polymer composites were 3–4 times higher than those of PCC–polymer composites at high PCC levels. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Abrasion Property of Epoxidized Natural Rubber

The abrasion resistance of two grades of epoxidized natural rubber (ENR 25 and ENR 50) and one grade of styrene-butadiene rubber (SBR) were studied using an Akron abrasion tester. An accelerated sulfur vulcanization system with 2-mercaptobenzothiazole (MBT) as the accelerator is used throughout the study. Carbon black (N 330), precipitated silica, and calcium carbonate were chosen as the fillers. The range of sulfur and filler loadings was from 1 to 5 phr and 10 to 50 phr, respectively. Mixing was done on a two-roll mill. Results obtained show that for all the rubbers studied, the volume loss due to abrasion decreases with increasing sulfur loading and passes through a minimum at about 3 phr of sulfur. This observation is attributed to the changes of cross-link types from monosulfidic to polysulfidic crosslink as sulfur concentration is increased. However, further sulfur loading would cause a “tight” cure, thus increasing the abrasion loss. For sulfur loading less than 3 phr, ENR 25 indicates the highest abrasion loss, followed by SBR and ENR 50. For the filled stock, minimum loss is observed at about 35–40 phr of filler. Reinforcing filler such as carbon black exhibits better abrasion resistance than calcium carbonate, a nonreinforcing filler. The abrasion loss increases at higher filler loading due to the dilution effect of fillers. Ozone plays an important role in the abrasion property of unsaturated rubbers, as reflected by the higher abrasion loss in the presence of ozone.     

碳酸钙改性聚碳酸亚丙酯研究

利用双螺杆挤出机研究了分别填充不同表面改性的碳酸钙后对聚碳酸亚丙酯片材专用料(PPC101)性能的影响。结果表明:随着碳酸钙(CaCO3)用量的增加,试样的维卡软化温度皆呈上升趋势,未进行表面处理的碳酸钙填料对PPC101维卡软化温度的提高更明显;填料是否进行表面处理对PPC101材料的拉伸性能影响不大,随着填料用量的增加,未进行表面处理和硬脂酸处理的碳酸钙填充PPC101材料的拉伸强度均呈先上升后基本稳定的趋势,而使用铝酸酯的碳酸钙填充PPC101材料的拉伸强度几乎不变;随着填料用量的增加,无论填料是否进行表面改性,试样的冲击强度和熔体质量流动速率均呈下降趋势;而且密度均呈线性上升趋势。     

Silane treated alumina trihydrate: A new formulating tool for flame retardant polyester fiber reinforced plastics

The high strength to weight ratio of glass reinforced plastics (FRF) combined with their fabrication flexibility has led to increasing use in new applications that no other materials could satisfy. FRF often replaces metals in traditional applications. Increasingly stringent flammability requirements have led to the use of alumina trihydrate filler, usually in combination with halogenated rosins. However, difficulties in compounding and fabrication often limit, the alumina trihydrate loading. This requires substantial increments of halogenated resin to meet specific flammability restrictions. In such composites, the price of the compound may be too high for a given application and one must often compromise substantially on both processing and physical property performance. Alumina trihydrate filled systems commonly suffer from poor glass fiber wet out and mold flow, with reduced strength and uniformity in fabricated parts. This paper describes how a unique silane pretreatment for alumina trihydrate permits bulk molding compound (BMC)/sheet molding compound (SMC) formulations to be developed with increased loadings of the filler, reduced filler wet out time, and improvements in glass dispersion, mold flow out, strength and uniformity of the composite. The paper also shows how the halogenated resin content of flame retarded systems may be minimized by the use of this silane treated alumina trihydrate.     

Mechanical properties of polypropylene composites reinforced with long glass fibres and mineral fillers

Abstract

The mechanical behaviour of long discontinuous glass fibre (LGF) reinforced polypropylene (PP) composites filled with talc or calcium carbonate fillers was studied. Sample specimens were processed by injection moulding, after which tensile and impact properties were analysed. In addition, scanning electron microscopy was used to analyse the morphology of the fracture surfaces. The results showed that the use of talc as a hybrid filler in LGF reinforced PP leads to a better tensile strength and toughness than in a corresponding hybrid composite based on calcium carbonate. Furthermore, it was observed that the matrix had a dominant role at low fibre content, whereas at high fibre loading, the effect of fibres was more evident.