Mechanical Properties Of Polyurethane Elastomers Research Articles

Study of stress wave attenuation characteristics of particle ceramic embedded polyurethane composites

In this paper, particle ceramic embedded polyurethane composites were prepared, and the dynamic and static mechanical properties of polyurethane elastomers were tested. Experiment and simulations were used to investigate the effects of different design parameters of polyurethane elastomers and particle ceramic on the stress wave attenuation of the composites. The microscopic morphology, energy absorption, and attenuation capabilities of the composites were analyzed and discussed. The results show that the polyurethane elastomers adheres well to the particle ceramic after impact and exhibits sufficient bonding with stable interfacial strength; As the volume fraction of particle ceramic increases, the energy absorption ratio also increases; The “harder” the polyurethane elastomer, the weaker the composite attenuation ability of stress waves. The function relationship between the composite attenuation ability of stress waves and the particle ceramic area occupy ratio and the number of stacked layers is obtained by fitting, which shows that the composite attenuation ability of stress waves is inversely proportional to the area occupy ratio and positively proportional to the number of stacked layers of particle ceramic.

Predicting the Mechanical Properties of Polyurethane Elastomers Using Machine Learning

Predicting the Mechanical Properties of Polyurethane Elastomers Using Machine Learning

Synthesis of Mono Ethylene Glycol (MEG)-Based Polyurethane and Effect of Chain Extender on Its Associated Properties.

This study depicts the investigations of the effect of composition of aromatic polyester polyol produced from terephthalic acid (TPA) and different concentrations of mono ethylene glycol (mEG) as a chain extender on the mechanical properties of polyurethane (PU) elastomer. Aromatic polyester polyols are prepared via the poly-esterification of adipic acid, terephthalic acid, catalyst, and mono ethylene glycol; while a polyurethane elastomer is formulated via the pre-polymerization of polyol with pure monomeric Methylene diphenyl diisocyanate (MDI.) Mechanical properties of polyurethane elastomers are examined, such as hardness via shore A hardness, apparent density via ASTM (American Society for Testing and Materials) D1622–08, and abrasion wear resistance via a Deutches Institut fur Normung (DIN) abrasion wear resistance tester. Structural properties are investigated through Fourier-transform infrared spectroscopy (FTIR) analysis. Results reveal that the shore A hardness of the PU elastomer increases with an increasing concentration of mEG from 4g to 12g. Nevertheless, the elastomer’s density depicts a reduction with an increasing extender content. The abrasion wear resistance of polyurethane, however, increases with an increasing concentration of glycol. A structural analysis through FTIR confirms the formation of polyurethane elastomer through the characteristic peaks demonstrated.

Effects of Modified Al2O3-Decorated Ionic Liquid on the Mechanical Properties and Impact Resistance of a Polyurethane Elastomer.

In this work, a new composite material with excellent dynamic impact resistance and outstanding quasi-static mechanical properties was synthesized. The composite material is composed of a polyurethane elastomer and a novel nano-polymer. The nano-polymer was composed of silane coupling agent-modified alumina microspheres and functionalized ionic liquids by double bond polymerization. The universal testing machine and split Hopkinson pressure bar were used to characterize the compression behavior, strength and energy absorption of the composite materials under static and dynamic conditions. Additionally, the comprehensive mechanical properties of polyurethane elastomer with different nano-polymer loadings (0.5–2.5 wt.%) were studied. The results show that whether it was static compression or dynamic impact, the polyurethane elastomer with 1% nano-polymer had the best performance. For the composite material with the best properties, its compressive yield strength under the static compression was about 61.13% higher than that of the pure polyurethane elastomer, and its energy absorption of dynamic impacts was also increased by about 15.53%. Moreover, the shape memory effect was very good (shape recovery is approximately 95%), and the microscopic damage degree was relatively small. This shows that the composite material with the best properties can withstand high compression loads and high-speed impacts. The developed composite material is a promising one for materials science and engineering, especially for protection against compression and impacts.

Effect of curing time on properties of polyether MDI polyurethane elastomer

In order to study the effect of curing time on the properties of polyurethane elastomers in MDI system and provide guidance for the production of polyurethane elastomers in this system, the effects of gradient (6-12h) curing time on the thermal stability and mechanical properties of polyurethane elastomers in polyether MDI system were studied in this paper. The results showed that the properties of polyurethane improved with the extension of curing time, and the mechanical properties of polyurethane tended to be stable when the curing time exceeded 10h.

Lignin-containing polyurethane elastomers with enhanced mechanical properties via hydrogen bond interactions

In this work, lignin-containing polyester polyol (LPES) was successfully synthesized by vacuum melting method with lignin instead of polyol, and then reacted with isocyanate and chain extender to obtain lignin-based polyurethane elastomer (LPUE). The effects of lignin as reactive raw material, chain extender, and filler on the structure, thermostability, mechanical performance, and self-healing properties of elastomers were systematically studied, respectively. The comprehensive mechanical properties of the obtained materials were significantly enhanced after the introduction of lignin, especially the maximum tensile strength increased to 26.6 MPa and elongation at break reached 408.6%, which were 1510.3% and 2130.5% higher than that of the original polyurethane elastomer (PUE). Results revealed that lignin in the hard segment had a significant effect on the thermal stability and mechanical properties of polyurethane elastomer, and lignin in the soft segment had an obvious impact on the healing properties. Due to the hydrogen bonding interaction of the polar groups in the molecular chain of lignin to form a microphase-ordered structure, LPUE with excellent mechanical properties can be obtained.

Effect of graphene loading on mechanical properties of polyurethane elastomer

Abstract The elastomeric polyurethane (PU) nanocomposites prepared by in- situ polymerization of diisocyanate with graphene nanoplatelets (GNPs) dispersion in polyol. Mechanical properties of polyurethane exhibited a significant improvement through incorporation of GNPs is observed. Morphologies study showed that there is a strong interaction between GNPs and hard segments of PU that allows effective load transfer. Two – dimensional structure of GNPs can help to prevent formation of crystalline hard segments. The tensile strength and tearing strength was improved by ∼1.9 times by with the incorporation of 1.0 vol. % of GNP.

Design of Azomethine Diols for Efficient Self-Healing of Strong Polyurethane Elastomers.

Azomethine diols (AMDs) were synthesized by condensation between a terephthalic aldehyde, polyether diamine, and ethanol amine. The synthesized AMDs were employed to introduce azomethine groups into the backbones of polyurethane elastomers (PUEs). Different AMDs were designed to control the concentration and distribution of azomethine groups in PUEs. In this study, we explored the intrinsic self-healing of AMD-based PUEs by azomethine metathesis. Particularly, the effects of the concentration and distribution of the azomethine groups on the AMD-based PUEs were considered. Consequently, as the azomethine group concentration increased and the distribution became denser, the self-healing properties improved. With AMD3-40, the self-healing efficiency reached 86% at 130 °C after 30 min. This represents a 150% improvement over the control PUE. Additionally, as the AMD content increased, the mechanical properties improved. With AMD3-40, the tensile strength reached 50 MPa. Therefore, we concluded that the self-healing and mechanical properties of PUEs can potentially be tailored for applications by adjusting the concentration and design of AMD structure for PUEs.

Effect of hard segment content on structure, dielectric and mechanical properties of hydroxyl-terminated butadiene-acrylonitrile copolymer-based polyurethane elastomers

Understanding the relationship between structure and dielectric property of dielectric elastomers (DEs) is very important in their practical applications. In this work, we fabricated polyurethane elastomers (PUEs) with high dielectric properties using hydroxyl-terminated butadiene-acrylonitrile copolymer (HTBN) as soft segment and hexamethylene diisocyanate (HDI) and butanediol (BDO) as hard segment (HS). We also investigated the effect of HS content on the structure, mechanical, dielectric and electromechanical properties of HTBN-based PUEs. The HTBN-based PUEs were achieved larger than 8.7 of dielectric constant and lower than 0.02 of dissipation factor at 1 KHz. The dielectric constant and dissipation factor of PUEs were slightly decreased with increase of HS segment, whereas the breakdown strength and Young's modulus of PUEs were significantly increased. The actuated area strain of PUEs also showed decreased with increase of HS content under the same electric field. Our results indicated that the adjusting of HD structure via HS content is one of effective ways to optimize the dielectric and mechanical properties of PUEs.

Effect of chain architecture of polyol with secondary hydroxyl group on aggregation structure and mechanical properties of polyurethane elastomer

Polyurethane elastomers (PUEs) based on poly(2-ethyl-1,3-hexamethylene adipate) glycol (PEHA), poly(2,4-diethyl-1,5-pentamethylene adipate) glycol (PDEPA) and poly(2-butyl-2-ethyl-1,3-trimethylene adipate) glycol (PBETA) were synthesized with 4,4’-diphenylmethane diisocyanate (MDI) and 1,4-butane diol (BD)/1,1,1-trimethylol propane (TMP). PEHA has one primary and one secondary hydroxyl groups, but PDEPA or PBETA has two primary hydroxyl groups. The effect of low reactive secondary OH group on molecular aggregation structure and mechanical properties of the PUEs was investigated using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), dynamic viscoelastic measurement and tensile testing. The study demonstrates that PEHA-based PUE has lower cross-linking density and lower degree of microphase separation than PDEPA- and PBETA-based PUEs. As a result, PEHA-based PUE has lower dynamic storage modulus value at the rubbery plateau region and Young's modulus.

Thermal and mechanical properties of two kinds of hydroxyl-terminated polyether prepolymers and the corresponding polyurethane elastomers

In order to analyze the differences in performance between two kinds of hydroxyl-terminated polyether (HTPE) binders, the curing reaction kinetics of the prepolymers and polyfunctional isocyanate (N-100) molecules and the thermal properties of the prepolymers and the corresponding polyurethane (PU) elastomers were studied by non-isothermal differential scanning calorimetry. The mechanical properties of PU elastomers were also studied by uniaxial tensile tests. With these data, the binder type could be chosen more appropriately for its application in rocket propellant formulations. The results showed that the reactivity of hydroxyl-terminated block copolyether (TPEG) with an isocyanate group is higher than that of hydroxyl-terminated random copolyether (PET). The chain flexibility of TPEG was less than that of PET, but the stereoregularity and crystallization ability of the former were superior. Compared to the prepolymers, the chain flexibility of the corresponding PU elastomers was reduced, and the crystallization ability became weaker such that their onset of crystallization was delayed. After the prepolymers were reacted with N-100, the thermal properties of PU elastomers remained consistent with their respective prepolymers. In summary, it was concluded that the mechanical properties of TPEG/N-100 PU elastomer films were found to be superior to the PET/N-100 films.

The Research on the Polyurethane Elastomers Based on Diphenylmethane Diisocyanate and Diamine Chain Extenders

This paper mainly describes the properties of mechanical properties, heat resistance, and dynamic mechanical properties of polyurethane elastomer based on MDI and diamine chain extenders. Compared with the polyurethane extended by diol, diamine extended MDI level polyurethane elastomer shows higher hardness, tensile strength, 300% modulus, tear strength and better heat resistance. But the soft segment relaxation shifts to higher temperature.

Simulation of variations in mechanical properties of polyurethane elastomers modified with carbon nanotubes

The addition of extremely small portions of single-wall carbon nanotubes causes an anomalous change in mechanical properties of a cross-linked polyurethane-amide-urea elastomer containing 10% of polyamide-6; namely, with a nanofiller content of hundredths and thousandths of a percent, local maxima of elastic modulus and ultimate stress are observed. In the work, the anomalous variation in the elastic modulus is simulated relying on the concept of intermediate phase layer formation at the boundary of contacting particles of the initial material.

Preparation and properties of adjacency crosslinked polyurethane-urea elastomers

Adjacency crosslinked polyurethane-urea (PUU) elastomers with different crosslinking density were prepared by using hydroxyl-terminated liquid butadiene-nitrile (HTBN), toluene diisocyanate (TDI) and chain extender 3,5-dimethyl thio-toluene diamine (DMTDA) as raw materials, dicumyl peroxide (DCP) as initiator, and N,N′-m-phenylene dimaleimide (HVA-2) as the crosslinking agent. The influences of the crosslinking density and temperature on the structure and properties of such elastomers were investigated. The crosslinking density of PUU elastomer was tested by the NMR method. It is found that when the content of HVA-2 is 1.5%, the mechanical properties of polyurethane elastomer achieve optimal performance. By testing thermal performance of PUU, compared with linear PUU, the thermal stability of the elastomers has a marked improvement. With the addition of HVA-2, the loss factor tanδ decreases. FT-IR spectral studies of PUU elastomer at various temperatures were performed. From this study, heat-resistance polyurethane could be prepared, and the properties of PUU at high temperature could be improved obviously.

Influence of Side Group Contents of Polycarbonate Glycol on Aggregation Structures and Mechanical Properties of Polyurethane Elastomers

Influence of Side Group Contents of Polycarbonate Glycol on Aggregation Structures and Mechanical Properties of Polyurethane Elastomers

Study on Mechanical Properties of Polyurethane Elastomers for Drum Scraper

Polyurethane elastomers (PUE) were prepared by casting method using the prepolymer and the chain extender. In here, the prepolymer synthesized by using poly(tetramethylene glycol ether) (PTMG) and toluene diisocyanate (TDI), the chain extender was a mixture of 3,5-dimetylthio toluene diamine (E-300) and triethanolamine. The effects of the NCO concentration in prepolymer, the molar ratio of E-300/triethanolamine, and the chain extension coefficient of NCO/NH2 on the mechanical properties of the prepared PUE were studied. The results showed that the prepared PUE possesses excellent mechanical properties which can meet the drum scraper’s application requirements when the NCO concentration in prepolymer was 5.06% and the molar ratio of composite chain extender was 0.92/0.08.

Influence of the type of chain extender and urethane group content on the mechanical properties of polyurethane elastomers with flexible hard segments

A study was made of how aspects of the mechanical response of polyurethane elastomers (PUs) based on poly(ethylene adipate) (PEA) vary with the number of CH2 methylene groups when using chain extenders of the type HO–(CH2)p–OH. The effect of varying the odd–even number of CH2 groups in regard to the chain extender was followed. The best mechanical behavior as elastomers was revealed for polyurethanes with CH2 even numbers on the chain extender, when the different parts of the PUs macromolecular chains can adopt extended linear forms. The effect of different concentrations of the hard segment content on a set of PUs based on PEA and 1,4-butanediol as chain extender was also studied. A hitherto overlooked isocyanate of variable geometry, 4,4′-dibenzyl diisocyanate was used in the PUs synthesis, based on a –CH2CH2– spacer group between the two aromatic rings.

Preparation and Mechanical Properties of Polyurethane Elastomer with Two Soft Segments of HTPB/PTMG

In this paper, a series of polyurethane elastomers (PUE) were prepared employing casting method using toluene diisocyanate (TDI), hydroxy-terminated butadiene-acrylonitrile copolymer(HTBN) and polytetrahydrofuran glycol (PTMG) as the main raw materials, and using 2,4- and 2,6- dimethylthioaromatic diamine (DMTDA) as a chain extender. The effects of the content of NCO in PUE (NCO%), mass ratio of HTBN/PTMG, molecular weight of PTMG, dosage of chain extender and heat treatment on the mechanical properties of PUE were studied. The results showed that the lower molecular weight of PTMG and the higher heat treatment temperature were both favorable for increasing the mechanical properties of PUE. When the mass ratio of HTBN/PTMG was 35:65, NCO% was 6.0%, molar ratio of NCO/NH2 was 1.20 and heat treatment time was 2h at 115 , the mechanical properties of PUE were best.

Force application and decay characteristics of untreated and treated polyurethane elastomeric chains.

In this study the effects of prestressing, environmental acidity, oxygen content, and temperature on mechanical properties were measured for three polyurethane-based orthodontic elastomeric chains. Specimens of each chain were treated for 10 and 100 days, and their mechanical properties were compared with those of the untreated specimens via stress-relaxation tests. Conditioning treatments were determined to affect the magnitude of residual load after relaxation, with the largest effect due to prestressing. Among the other variables studied, an increase in temperature of the environment appeared to significantly influence the degradation mechanism responsible for the deterioration of the mechanical properties of polyurethane elastomers (p < 0.001); acidity and oxygen content had no significant effects. Force decay profiles from the specimens were derived using a Maxwell-Weichert model consisting of springs and dashpots. This model allows the orthodontist to predict load magnitude supplied by the chain at activation and at any time during treatment.

Effect of side groups of polymer glycol on microphase‐separated structure and mechanical properties of polyurethane elastomers

AbstractThe effect of side methyl and dimethyl groups of the soft segment component on the microphase‐separated structure and mechanical properties of polyurethane elastomers (PUEs) was investigated. Poly(oxytetramethylene) glycol (PTMG), and PTMG incorporating dimethyl groups (PTG‐X) and methyl side groups (PTG‐L) were used as a polymer glycol, which forms a soft segment in the PUEs. The PUEs were synthesized with 4,4′‐dipheylmethane diisocyanate [1,1′‐methylenebis(4‐isocyanatobenzene)], 1,4‐butane diol, and 1,1,1‐trimethylol propane by a prepolymer method. The degree of microphase separation of the PUEs became weaker with increasing side group content in polymer glycols. Dynamic viscoelastic properties measurement showed reorganized‐crystallization and melting of the soft segment for the PUEs based on PTMG, PTG‐L, and PTG‐X with a lower content of the side groups, but not for a PTG‐L and PTG‐X with higher content of the side groups. Tensile testing revealed that increasing methyl group concentration made the PUEs soften and weaken. The PTMG‐based PUEs obviously exhibited strain‐induced crystallization of the soft segment chains during elongation process. In contrast, for the PTG‐L and PTG‐X‐based PUEs, crystallinity decreased with increasing side group content, and the PUEs with PTG‐L and PTG‐X with highest methyl group content did not crystallize even at a large strain. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2054–2063, 2008