Polyurethane Elastomer Matrix Research Articles

Impact resistance of polyurethane elastomer enhanced by organic montmorillonite with interlayer anchored polymer chains

AbstractThe development of materials with excellent impact resistance is essential for safety protection. Polyurethane elastomer (PUE) is widely used in impact protection; however, it has low dynamic compressive strength and poor energy absorption efficiency under high‐speed impact, limiting its in‐depth application in the protection field. Herein, an organic montmorillonite (MMT) with interlayer anchored polymer chains, named M@NH3+, was synthesized via the dual modification of MMT involving surface grafting and cation intercalation by macromolecular amino silane, which was used to enhance the impact resistance of PUE. Based on the uniform dispersion of M@NH3+ within the PUE matrix, the strong bonding at the polymer‐filler interface and the synergistic action between M@NH3+ lamellae, PUE‐M@NH3+ composite exhibited excellent mechanical properties and energy absorption capacity. Compared with pure PUE, the elastic modulus (+98.3%), static compressive strength (+37.0%), dynamic compressive strength (+35.4%) and impact energy absorption (+50.8%) of PUE‐2wt%M@NH3+ were significantly improved, which shows that it has potential applications in the field of high‐speed impact protection.Highlights Organic MMT with interlayer anchored polymer chains was prepared. The large interlayer spacing of M@NH3+ facilitates its dispersion within the matrix. The interconnected M@NH3+ lamellae can collaboratively disperse impact stress. The impact energy absorption of PUE composite has been remarkably improved.

Fabrication of a durable anti-icing composite coating based on polyurethane elastomer and silica nanoparticles

In order to design and fabricate hydrophobic, durable and anti-icing coating for aircraft, a polyurethane elastomer matrix was hydrophobically modified and incorporated with fluorinated SiO2 nanoparticles to prepare a micro/nanostructured coating. The micro/nanostructured coating with low surface energy displayed significantly improved mechanical properties and hydrophobicity, which exhibited the water contact angle of 162° as well as the sliding angle of 2°. The coating is highly stretchable, which could sustain large-scale extension, and exhibits tensile strength and elongation at break up to 16.22 MPa and 385%, respectively. Furthermore, the coating exhibited a remarkably weak ice adhesion strength of 14.33 kPa, on which the accumulative ice is prone to fall off under natural wind and its own weight. The coating sustained long-term superhydrophobic properties and anti-icing performance even after 1000 abrasion cycles. The proposed method for the production of scalable superhydrophobic coating is cost-effective and can be applied in aerospace and automotive anti-icing systems.

A composite nanofiller with a nail column void structure to imitate beetle shell fiber to enhance the impact resistance of polyurethane elastomer

Polyurethane elastomer (PUE) is faced with cracking problems under the high-speed impact to limit its application in the protective field. Inspired by a “nail columns"—"nail columns” void structure of chitin fiber on the beetle shell, tetra vinyl polyhedral oligomeric silsesquioxanes (EVPOSS) composite multiwalled carbon nanotube (MCNTs) enhanced fillers (PDVBMC and PNHMC) were prepared by different bonding types and used to improve the impact resistance of PUE. The 1.5 wt% PDVBMC or PNHMC reinforced composite PUE exhibited simultaneous enhancements in maximum compression modulus (22.2% and 34.6%), energy absorption (40.1% and 53.7%) and storage modulus (16.5% and 30.6%). The excellent mechanical properties of composite PUE is not only attributed to the enhancement of interface strength between enhanced fillers and PUE matrix but also the bonding strength between enhanced fillers, which can be demonstrated by the differences in energy absorption, storage modulus and bonding fracture energy.

In Situ Grafted Composite Nanoparticles-Reinforced Polyurethane Elastomer Composites with Excellent Continuous Anti-Impact Performance.

Polyurethane elastomer (PUE) has attracted much attention in impact energy absorption due to its impressive toughness and easy processability. However, the lack of continuous impact resistance limits its wider application. Here, an amino-siloxane (APTES) grafted WS2-coated MWCNTs (A-WS2@MWCNTs) filler was synthesized, and A-WS2@MWCNTs/PUE was prepared by using the filler. Mechanical tests and impact damage characterization of pure PUE and composite PUE were carried out systematically. Compared with pure PUE, the static compressive strength and dynamic yield stress of A-WS2@MWCNTs/PUE are increased by 144.2% and 331.7%, respectively. A-WS2@MWCNTs/PUE remains intact after 10 consecutive impacts, while the pure PUE appears serious damage after only a one-time impact. The improvement of mechanical properties of A-WS2@MWCNTs/PUE lies in the interfacial interaction and synergy of composite fillers. Microscopic morphology observation and damage analysis show that the composite nanofiller has suitable interfacial compatibility with the PUE matrix and can inhibit crack growth and expansion. Therefore, this experiment provides an experimental and theoretical basis for the preparation of PUE with excellent impact resistance, which will help PUE to be more widely used in the protection field.

Enhanced effect of OMMT and KH-Al2O3 on polyurethane composite mechanical properties

Sodium montmorillonite (MMT) was modified by octadecyl trimethyl ammonium chloride (OTAC) via cation exchange to obtain organo-montmorillonite (OMMT), Al2O3 was treated by KH-550 (3-Aminopropyltriethoxysilane) to get KH-Al2O3. The polyurethane elastomer (PUE) was synthesized with 4,4′-diphenylmethane diisocyanate (MDI), polypropylene glycol (PPG) and 1,4-butanediol (BDO) as the raw materials. And then, OMMT/KH-Al2O3/PUE composite was prepared by the prepolymer method; PUE was the matrix, OMMT and KH-Al2O3 were reinforcements. The micro-morphology and mechanical properties of OMMT/KH-Al2O3/PUE composites were measured and analyzed. The results of FT-IR and XRD showed that OTAC had been introduced into MMT layer and the layer spacing of OMMT had increased. The KH-550 had successfully grafted to the surface of Al2O3 to obtain KH-Al2O3. The TEM results demonstrated the interaction between OMMT and KH-Al2O3, weakening the interaction between the same molecules and the OMMT sheet was further peeled off. The SEM images displayed that a specific ratio of OMMT and KH-Al2O3 had excellent dispersion in the PUE matrix. The mechanical properties of OMMT/KH-Al2O3/PUE composites were significantly better than those of OMMT/PUE and KH-Al2O3/PUE composite. The maximum tensile strength, elongation at break and tensile strength at break are 21.82 MPa, 668% and 19.98 MPa, respectively, which were 43.8%, 29.2% and 36.8% higher than that of PUE matrix, when the content of inorganic components was 3 wt% and the mass rate of OMMT to KH-Al2O3 was 1:1. This composite material is a kind of excellent polyurethane elastomer and widely is maybe used in mechanical accessories, pipe, mining and metallurgy industries.

Investigation of the rubber elasticity and properties of polyurethane elastomers with different silicon carbide contents

Silicon carbide (SiC) powder was added to a polyurethane elastomer (PUR) to produce the composites. PUR was synthesized by mixing polyether polyol (PETP, Mw = 6000 g/mol) and 4,4′diphenylmethane diisocyanate. The stress-strain curves were carried out to estimate the effect of SiC on rubber elastic behaviour of PUR composites. As SiC content increases, the rubber elasticity region is noticeably decreased which can clearly be seen in the stress-strain curve, this could be attributed to the distribution of the SiC particles in the PUR matrix which prevents the cross-linking chain mobility of PUR and therefore affects the deformation while stretching. Furthermore, the decrease in the elongation at break is also co-related to the SiC content which hindrance the molecular mobility of the PUR chain. Shore A and D hardness increase by increasing SiC content up to 88 Shore A and 37 Shore D at 30 wt.% SiC. This is mainly due to the addition of SiC particles which act as active fillers in PUR matrix. The tensile strength and Young’s modulus are slightly increased when SiC content was increased. These observations support that Sick particles act as reinforcement which is active fillers and affect the stiffness in the elastic deformation of PUR.

The morphology and structure of natural clays from Yangtze River and their interactions with polyurethane elastomer

In thermoplastic polyurethane elastomer (PUE) technology, the necessity for revealing the interactions between clays and polyurethane chains is improving recently. In this paper, three different natural clays (NC) were firstly employed to prepare NC/PUE composites to explore the relation between fillers and PUE chains. We found that the natural clays were formed from sand to fertile soil, and then corroded deeply to CaCO3 (rock) by surroundings, including water, wind and temperature and so on. Then, the neat PUE and NC/PUE composites were characterized by SEM, TEM, XRD, SAXS, FTIR and DSC to investigate the function of natural clays in polyurethane chains. We found that the different clays particles interacted with PUE chains in different ways. The lamellae and stacks of rock aggregated mainly in PUE matrix and interact with the hard/soft domains, while that of sand and soil aggregates mainly on the surface of PUE matrix.

Effect of Molybdenum Trioxide-Loaded Graphene and Cuprous Oxide-Loaded Graphene on Flame Retardancy and Smoke Suppression of Polyurethane Elastomer

Molybdenum trioxide (MoO3)-loaded graphene (MoO3-GNS) hybrids and cuprous oxide (Cu2O)-loaded graphene (Cu2O-GNS) hybrids were successfully prepared via the hydrothermal method and one-pot coprecipitation method, respectively. Subsequently, the MoO3-GNS and Cu2O-GNS hybrids were incorporated into a polyurethane elastomer (PUE) matrix, respectively, and their effects on thermal stability, flame retardancy, and smoke suppression properties of PUE were investigated. Thermogravimetric analysis results showed that the incorporation of 2.0 wt % MoO3-GNS or Cu2O-GNS hybrids efficiently improved the char yield of the PUE matrix. Moreover, the addition of MoO3-GNS or Cu2O-GNS hybrids presented excellent flame retardancy and smoke suppression properties of PUE composites, as evidenced by the obvious reduction in their heat release rate, total heat release, and smoke density. The improvement in the flame retardancy and smoke suppression properties were mainly attributed to the synergistic effect between the physical...

Influence of nanosilica on the morphology, thermal and mechanical properties of polyurethane elastomer

AbstractIn this article, the influence of fumed silica nanofiller on the structure and properties of segmented polyurethane elastomer (PUR) was investigated. In order to investigate the interactions at the filler–matrix interface, nonmodified and commercially modified fillers (with methacrylsilane and octylsilane) were used. The PUR composites with 1.0, 2.0, 4.0, 6.0, and 9.0 vol % of all fillers were prepared by solution casting method. Surface free energy of the fillers and polymer matrix was determined using contact angle measurements with different testing liquids. Change in morphology was analyzed using optical polarization microscopy and distribution of the filler in polymer matrix using scanning electron microscopy. The influences of silica fillers on mechanical and thermal properties of PUR were investigated. Results showed that surface treatment of silica filler with methacrylsilane and octylsilane reduces the agglomeration of particles that improves dispersion at microlevel. Addition of all fillers disrupts spherulite morphology and decreases crystallinity of the PUR matrix. Nonmodified silica nanofiller has the least pronounced influence on spherulite morphology and the lowest influence on polyurethane crystallinity and thus the best mechanical properties. Surface modification of silica with octylsilane has less influence on polyurethane crystallinity and on decreasing of mechanical properties than modification with methacrylsilane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

High magnetostriction polymer-bonded Terfenol-D composites

Different magnetostrictive composites that contain Terfenol-D particles in a polyurethane elastomer matrix were prepared by changing the ratio of the hard/soft segment ( F) of the polyurethane, and modifying the amount of Terfenol-D particles, from 30 to 50 wt%. The magnetostrictive behaviour, as well as the mechanical properties of the magnetic composites, has been investigated. The magnetostriction was measured at room temperature with strain gauges (and parallels) in magnetic fields up to 1 T. The magnetostrictive response improves when the magnetic particles are oriented in different magnetic fields (0.05, 0.5 and 1 T) and reaches ≈700 microstrains for an oriented F = 1 and 50% of Terfenol-D sample. On the other hand, the effect of the matrix on the magnetostrictive response has been examined, obtaining the highest response for a F = 1.5 polyurethane and 50 wt% of Terfenol-D oriented with a magnetic field of 0.5 T.

Modeling the stress/strain behavior of a knitted fabric-reinforced elastomer composite

This paper presents a micromechanical analysis procedure for predicting the stress/strain behavior of a composite made of weft-knit polyester fiber interlock fabric and a polyurethane elastomer matrix. For analysis, a representative volume element (RVE) of the composite was initially identified. The RVE was divided into a number of sub-volumes, each of which was considered as a unidirectional fiber-reinforced composite oriented according to the fiber architecture in the RVE. The analysis was then carried out for such a unidirectional composite by using a bridging matrix that correlates the stresses generated in both the fiber and the matrix materials. The bridging matrix is sensitive to the geometrical and physical properties as well as the constitutive relationships of the fiber and matrix materials. The Prandtl–Reuss theory was used to describe the elasto-plastic behavior of the polyester fiber and an accurate incremental theory was applied to represent the rubber-elastic constitutive relationship of the polyurethane matrix. A volume-average scheme was used to assemble the contributions of all the sub-volumes to obtain the overall response charecteristics of the RVE. By means of the bridging matrix, the stress state of each constituent phase of the composite is explicitly known at every load step. The procedure was repeated for a series of load increments to obtain the stress/strain behavior of the composite. A strength criterion based on maximum normal stress theory was applied to determine the maximum load that the composite can sustain. The predicted stress/strain behavior is validated by comparison with experimental data.