On the effect of the polyketone structure on the strength properties of thermoplastic-matrix fiber glass composites

The physical, mechanical, and structural-relaxation properties of composite microplastics based on thermoplastic (polyethylene and polyamide) matrices, in which the alternating ethylene-CO, diene-CO, and ethylene-CO-α-olefin copolymers are used as a finish, were studied. An important role of the interface between the components in the formation of the mechanical properties of thermoplastic-matrix composites and the possibility of controlling adhesive interactions by means of polymeric finishes based on poly(diene-ketone)s and aliphatic polyketones with different side-chain lengths are shown.     

热塑性淀粉/乙烯-乙烯醇共聚物复合材料的制备与性能

利用熔融共混的方法,制备得到热塑性淀粉/乙烯-乙烯醇共聚物（TPS/EVOH）复合材料,并对该复合体系的加工性能、机械性能、动态力学性能、流变性能以及吸水性进行了研究.结果表明：随着EVOH含量增加,复合材料中分子间作用力加强;复合体系的机械性能得到改善;当EVOH含量到达30%后,复合材料的吸水性明显降低.     

Interfacially modified LDPE/GTR composites with non-polar elastomers: From microstructure to macro-behavior

This paper provides some new insights into the mechanism of interaction and modifications in thermoplastic composites based on low density polyethylene (LDPE), ground tire rubber (GTR) and non-polar elastomer. The composites were prepared using a co-rotating twin-screw extruder at variable LDPE/GTR ratio and constant elastomer content. Two types of commercial elastomer were applied: styrene-butadiene-styrene (SBS) block copolymers (Kraton^®) with different topologies (linear/branched) and partially cross-linked butyl rubbers (Kalar^®) with different Mooney viscosities. Processing characteristics, static mechanical properties (tensile strength, elongation at break, hardness), dynamic mechanical properties, thermal properties and morphology of the resulting thermoplastic composites were investigated. Microstructure analysis shows that modification of LDPE/GTR composites with non-polar elastomers caused encapsulation of GTR particles within the elastomer phase. This phenomenon has significant influence on macro-behavior of thermoplastic composites based on LDPE/GTR blends. The results indicate that SBS copolymer improves interfacial interactions between GTR and LDPE, which enhances mechanical and thermal properties of the composites. On the other hand, cross-linked butyl rubber showed partial compatibility with LDPE and low compatibility with GTR particles.     

Structure and composition of polymer-bitumen composites

Features of the composition and structure of polymer-bitumen composites are examined, including the effects of the amount and quality of the basic components on the characteristics of the final product. The effect of butadiene-styrene thermoplastic elastomer on the properties of the cold applied polymerbitumen mastic is considered. Typical component mixing schemes are analyzed, and a flowsheet for production of polymer-bitumen mastic is presented.     

DSC investigations of polyamide 6 in hybrid GF/PA 6 yarns and composites

Glass/PA 6 composites were manufactured from specially designed hybrid yarns. The hybrid yarns were produced by three different spinning systems: friction spinning, ring twisting and pneumatic texturing. Each of these systems gives a different structure of the yarn and a different level of blending of the reinforcing and thermoplastic fibres. The crystallization and melting behaviour of PA 6 in the yarns and the composites were studied by differential scanning calorimetry.

The different structure of the hybrid yarns leads to differences in the crystallinity of PA 6 in the yarns and the composites. The mechanical properties of the thermoplastic yarns and the composites are influenced, among other factors, by the crystal structure of the polymer.     

Mechanical Properties and Dynamic Mechanical Analysis of Thermoplastic-Natural Fiber/Glass Reinforced Composites

The mechanical properties and dynamic behavior of thermoplastic composites based on polypropylene/glass fibers and polypropylene/natural fibers (i.e. kenaf, hemp, flax) are presented. A survey is given on some aspects, crucial for the use of these composites in structural and non-structural components such as their vibration-damping response, in relation to the composite compaction level and the manufacturing procedure. In order to investigate a wide vibration frequency range, including acoustic frequencies, different testing techniques, both with forced and free vibrations, were applied. A comparison between natural fiber and glass fiber reinforced laminates is presented. Compaction levels, allowing to obtain the best compromise between mechanical performance and damping response, are investigated.     

The effect of the manufacturing procedure on the electric properties of carbon-black-filled,fiberglass-reinforced thermoplastic composites

The electric properties of carbon-black-filled, fiberglass reinforced thermoplastic composites with unidirectional and random structure were studied. Their samples were prepared according to various manufacturing processes: injection molding, molding, press molding, winding, and pultrusion. It was shown that the electric properties of the composites are determined by the character of distribution of filler particles in the polymer matrix, which is closely related to the blending parameters and the engineering properties of the material.     

Mechanical properties and enzymic degradation of thermoplastic and granular sago starch filled poly(ε-caprolactone)

The mechanical, morphological and biodegradation properties of two types of poly(ε-caprolactone)/sago starch (PCL/sago) composites were investigated i.e. dried granulated sago starch and undried thermoplastic sago starch (TPSS). Thermoplastic starch was extruded with a twin screw extruder model Haake Rheomix (TW100 attached to a Haake Rheometer (Haake Rheodrive 5000). The composites were compounded with a Haake internal mixer (Haake Rheomix 3000) attached to the Haake Rheometer. Tensile properties were determined with the Monsanto Tensometer T10. A Shimadzu UV-160A visible UV spectrophotometer was used to monitor the liberation of carbohydrate as a consequence of starch hydrolysis by α-glucoamylase. Determining the weight loss of composites as well as the acid liberated from PCL also monitored biodegradation. The results indicate that dried granulated sago starch function better as fillers in terms of mechanical properties and the ease of biodegradation. However, TPSS imparted better yield strength to the composites. Poor wetting of starch accounts for the decreased mechanical properties at higher starch concentration as agglomeration occurs. While the rigid granular starch retained their shape in the composites, thermoplastic starch that is surrounded by microvoids is easily deformed due to plasticization.     

Dispersion evaluation of microcrystalline cellulose/cellulose nanofibril-filled polypropylene composites using thermogravimetric analysis

Microcrystalline cellulose-filled polypropylene (PP) composites and cellulose nanofiber-filled composites were prepared by melt blending. The compounded material was used to evaluate dispersion of cellulose fillers in the polypropylene matrix. Thermogravimetric analysis (TG) and mechanical testing were conducted on composites blended multiple times and the results were compared with single batch melt blended composites. The residual mass, tensile strength, and coefficient of variance values were used to evaluate dispersion of the microcrystalline cellulose fillers in the PP matrix. The potential of using TG to evaluate cellulose nanofiber-filled thermoplastic polymers was also investigated and it was found that the value and variability of residual mass after TG measurements can be a criterion for describing filler dispersion. A probabilistic approach is presented to evaluate the residual mass and tensile strength distribution, and the correlation between those two properties. Both the multiple melt blending and single batch composites manufactured with increased blending times showed improved filler dispersion in terms of variation and reliability of mechanical properties. The relationship between cellulose nanofiber loading and residual mass was in good agreement with the rule of mixtures. In this article, the authors propose to use a novel method for dispersion evaluation of natural fillers in a polymer matrix using TG residual mass analysis. This method can be used along with other techniques such as scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD) for filler dispersion evaluation in thermoplastic composites.     

Thermoplastic modification of monomeric and partially polymerized Bisphenol A dicyanate ester

Bisphenol A dicyanate ester (BADCy) was modified with different amounts of an engineering thermoplastic, polysulfone (PS) to improve impact strength of the parent resin. Differential scanning calorimetry of the blends suggested that addition of PS widens the curing exotherm of the BADCy considerably. FTIR of cured neat resins indicated total conversion of cyanate functional groups into triazine rings by cyclotrimerization. The cured neat resins showed phase separated morphology with cyanate ester as the continuous phase. The modified resins were shown to have better thermal, hygrothermal and impact strength properties. However, when glass fiber reinforced composites were made using partially polymerized BADCy and PS, very little or no phase separation in the resin was noticed. Flexural and impact strength measurement of composites showed that PS modification has compromised the flexural properties and only retained the impact strength of the parent resin containing composite. This study thus suggests that improvements realized in thermoplastic modification of monomeric BADCy are not directly transferable to composites using a partially prepolymerized BADCy.     

Processing of product forms for the large-scale manufacturing of advanced thermoplastic composites

In the field of large-volume applications today, injection-moldable polymers, reinforced with short or long fibers, are used for semi-structural components. Additional use is made of glass mat thermoplastic sheets, for which the processing technologies have already been established in a large number of applications. Advanced thermoplastic composites based on highly aligned, continuous fibers represent, with their high fiber content, a big step in terms of mechanical performance and offer thermoplastic polymers the chance to become structural components. In spite of a great deal of work carried out in this category of materials, in particular with carbon fiber-based products for defense and aerospace applications, the business is still at an early stage of development due to the high price of intermediate products (small plants and not fully optimized production processes) and to embrionic manufacturing technologies for mess production applications. Conversion of the various continuous fiber reinforced thermoplastic materials into useful parts and components is dependent on the intermediate product forms: boardy tape, flexible two, fabric or sheet. Some general technologies exist for the thermoplastic composites and their subsequent processing methods; however, in many cases because of the peculiarity of these products (i.e. fabric deformation under stamping) they require different approaches. The scope of this work is to describe those methods that are most promising for large-volume applications, in particular products forms (containing powder) for post-shaping impregnation, and to analyze some of the fundamental mechanisms of flow and deformation that drive the processing behavior.     

Flame retardant and thermal degradation properties of flame retardant thermoplastic polyurethane based on HGM@[EOOEMIm][BF4]

Journal of Thermal Analysis and Calorimetry - This article mainly studies the flame retardant and thermal degradation properties of thermoplastic polyurethane (TPU) composites based on...     

Thermal transfer,interfacial, and mechanical properties of carbon fiber/polycarbonate-CNT composites using infrared thermography

Electrical resistance (ER) and thermogram measurements were used to evaluate thermal transfer, interfacial and mechanical properties of carbon fiber reinforced thermoplastic polycarbonate composites. Carbon nanotubes (CNTs) were fairly uniformly dispersed in polycarbonates using a solvent dispersion method. The CNTs were then further dispersed with an additional time using a twin screw extruder. The effect of CNT on the mechanical properties of polycarbonate was evaluated using a thin film tensile test. For thermogram to evaluate the transferring temperature the composite was placed on a hotplate and copper wires were inserted in the composite at uniform thickness intervals. Due to the different inherent thermal conductivity of CNT, ER was measured to detect thermal changes in the carbon fiber/CNT-polycarbonate composites. The comparison of interlaminar shear strength (ILSS) was to investigate effects of CNT on mechanical and interfacial properties. The uniform distribution of CNTs affected all of these properties in carbon fiber-reinforced thermoplastic composite. Furthermore, heat transfer and heat release become more rapid with the addition of CNT than the without case.     

Effect of nanotube functionalization on the properties of single‐walled carbon nanotube/polyurethane composites

A commercially available aliphatic thermoplastic polyurethane formulated with a methylene bis(cyclohexyl) diisocyanate hard segment and a poly(tetramethylene oxide) soft segment and chain‐extended with 1,4‐butanediol was dissolved in dimethylformamide and mixed with dispersed single‐walled carbon nanotubes. The properties of composites made with unfunctionalized nanotubes were compared with the properties of composites made with nanotubes functionalized to contain hydroxyl groups. Functionalization almost eliminated the conductivity of the tubes according to the conductivity of the composites above the percolation threshold. In most cases, functionalized and unfunctionalized tubes yielded composites with statistically identical mechanical properties. However, composites made with functionalized tubes did have a slightly higher modulus in the rubbery plateau region at higher nanotube fractions. Small‐angle X‐ray scattering patterns indicated that the dispersion reached a plateau in the unfunctionalized composites that was consistent with the plateau in the rubbery plateau region. The room‐temperature modulus and tensile strength increase was proportionally higher than almost all increases seen previously in thermoplastic polyurethanes; however, the increase was still an order of magnitude below what has been reported for the best nanotube–polymer systems. Nanotube addition increased the hard‐segment glass transition temperature slightly, whereas the soft‐segment glass transition was so diffuse that no conclusions could be drawn. Unfunctionalized tubes suppressed the crystallization of the hard segment; whereas functionalized tubes had no effect. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 490–501, 2007     

Thermoplastic starch blends: A review of recent works

The aim of this review is to discuss the recent developments in thermoplastic starch blends. Starch has been considered as an excellent candidate to partially substitute synthetic polymer in packaging, agricultural mulch and other low-cost applications. Recently, the starch granules were plasticized using different plasticizers under heating and shearing, giving rise to a continues phase in the form of a viscous melt which can be processed using traditional plastic processing techniques, such as injection molding and extrusion. This kind of starch composites is called thermoplastic starch. Unfortunately, thermoplastic starch presents some drawbacks, such as low degradation temperatures, which make it difficult to process, poor mechanical properties and high water susceptibility. Much work has been carried out to overcome these drawbacks, including the combination of thermoplastic starch with other polymers, aiming at lowering the cost and enhancing the biodegradability of the final product.     

The effect of surface coating of CNTs on the mechanical properties of CF‐filled HDPE composites

Mechanical properties of carbon fiber (CF) and carbon nanotube (CNT)‐filled thermoplastic high‐density polyethylene (HDPE) composites were studied with particular interest on the effects of filler content and fiber surface treatment by coupling agent. Surface‐treated CF‐filled HDPE composites increased their tensile strength and impact strength, which is further increased with the addition of CNT. SEM showed that CNT‐coating‐treated CF‐HDPE composites show better dispersion of the filler into the matrix, which results in better interfacial adhesion between the filler and the matrix. Copyright © 2014 John Wiley & Sons, Ltd.     

Synergistic effects between hollow glass microsphere and ammonium polyphosphate on flame-retardant thermoplastic polyurethane

It is mainly studied that the smoke-suppression properties and synergistic flame-retardant effect of hollow glass microsphere (HM) in flame retardant thermoplastic polyurethane (TPU) composites based on ammonium polyphosphate (APP) as a flame-retardant. Also, the smoke suppression properties and flame-retardant effect were investigated by smoke density test (SDT), cone calorimeter test (CCT), limiting oxygen index, and thermogravimetric analysis, separately. The char residues left after CCT were examined by scanning electron microscopy. The data of SDT shows that HM could effectively decrease smoke production of TPU composites. The results of CCT reveal that the system of APP/HM could reduce heat release rate, smoke production rate, and total smoke release. It is shown that APP/HM is a good system with smoke-suppression and synergistic flame-retardant properties in flame-retardant TPU composites.     

Properties of wood-polymer composites with a polymer matrix containing sevilens

The effect of vinylacetate unit content in sevilen used as a polymer matrix or polyethylene compatibilizer on the properties of wood-polymer composites with a thermoplastic binders and filler of plant origin is studied. It is shown that the introduction of vinylacetate units decreases the tensile strength, contact elastic modulus, Brinell hardness, and water absorption of the composites, but increases the relative tensile elongation and impact viscosity without notch.     

Fabrication of thermoplastic polyurethane composites with a high dielectric constant and thermal conductivity using a hybrid filler of CNT@BaTiO3

Thermoplastic polyurethane composites with an excellent dielectric constant and high thermal conductivity were obtained using CNT@BaTiO₃ as a filler through a low-speed melt extrusion method. Before preparing the hybrid filler for the composite, the filler particles were surface modified to ensure that the outer surfaces could facilitate the reaction among particles to form the hybrid and ensure complete dispersion in the thermoplastic polyurethane matrix. After confirming the proper surface treatment of the filler particles using infrared spectroscopy, thermal degradation analysis and field emission scanning electron microscopy, they were used to prepare the composite materials at a processing temperature of 200 °C. The thermal stability, thermomechanical properties, mechanical properties, thermal conductivity, and dielectric properties of the composites were investigated. Compared to the neat thermoplastic polyurethane matrix, the prepared composite exhibited a higher thermal stability, approximately 300% higher storage modulus, higher tensile strength and elongation at break values, approximately three times higher thermal conductivity (improved from 0.19 W/(m.K) to 0.38 W/(m.K), and approximately five times larger dielectric constant at high frequencies (at 1 MHz a dielectric constant of 19.2 was obtained).     

Influence of hybridization on in-plane shear properties of 2D & 3D thermoplastic composites reinforced with Kevlar/basalt fabrics

This paper investigates the characterization of in-plane shear properties of thermoplastic composites reinforced with Kevlar/basalt fabrics. Different fabrics had architectures of two dimensional plain woven (2D-P) and three dimensional angle-interlock (3D-A). Intralayer hybridization was performed during the weaving of the fabrics with the combination of Kevlar and basalt yarns. Five 2D-P and three 3D-A composite laminates were manufactured with polypropylene (PP) as a matrix, using compression molding. Iosipescu shear tests were carried out to evaluate the in-plane shear properties. The experimental results revealed that the shear properties including shear modulus, shear strength and shear failure strain of homogeneous composites were improved by 6.5–14.9%, 4.3–19.7%, and 3.2–46.7%, respectively. Similarly, change in the fabric architecture from 2D-P to 3D-A also enhanced the shear strength and shear failure strain by 32.0–41.6% and 7.2–22.5%, respectively. Intralayer hybrid composites had better in-plane shear properties than the interlayer hybrid composites. The fracture morphologies of the specimens were examined by scanning electron microscopy (SEM).