One-Pot Synthesis of Supertough,Sustainable Polyester Thermoplastic Elastomers Using Block-Like,Gradient Copolymer as Soft Midblock

It remains challenging to synthesize supertough thermoplastic elastomers(TPEs)since the stretchability and tensile strength are mutually exclusive.Here,we report a one-pot strategy for the preparation of sustainable,triblock polyester TPEs consisting of poly(L-lactide)(PLLA)hard segments and poly(ɛ-caprolactone)-co-poly(δ-valerolactone)(PCVL)soft segments.The TPEs were synthesized successfully with high stretchability(up to 2100%)and strong tensile strength(up to 71.5 MPa)without requiring specific functionalized groups by simply adjusting the polymer microstructures,which,in turn,exhibited a world’s record toughness of 445 MJ/m^(3).Systematic investigation revealed that the block-like,gradient microstructure of PCVL improved the ductility by providing a flexible elastic network and enhancing the tensile strength through strain-induced crystallization.The practicability of this strategy was well demonstrated by lifting a water tank over 30,000 times heavier than itself and easy scale-up experiments.

Hydrogen Bonding in Thermoplastic Polyurethane Elastomers:IR Thermal Analysis

The hydrogen bond percentage and its temperature dependence of the three TPU samples synthesized from polytetrahydrofuran, 4,4’-diphenylmethane diisocyanate, N -methyl diethanol amine or 1,4-butane diol were studied by means of IR thermal analysis. The enthalpy and the entropy of the hydrogen bond dissociation were determined by the Van’t Hoff plot.

Fabrication and Characterization of Poly(Styrene-Butadiene-Styrene)/Thermoplastic Polyurethane Blends

This investigation presents thermoplastic elastomers (TPEs) based on poly (styrene-butadiene-styrene) (SBS) and thermoplastic polyurethane (TPU) materials were prepared with varying compositions. A series of works were conducted on the relationships between rheological, optical properties, morphology, mechanical properties, abrasion resistance and thermostability given. The results showed that the shear viscosity of SBS not obvious effect with TPU content. The optical properties of the SBS/TPU blend that its uniform transparency. The morphology characteristics indicating the phase diversion and the variation in the size of the SBS domains from large to small as the TPU contents increased, with heterogeneous domain dispersions. Additionally, the mechanical properties, abrasion resistance and thermal resistance are improved as the amount of added TPU is increased, suggesting that the blending of SBS with TPU is consistent with the compound rule.

High-Performanceα-Diimine Nickel Complexes for Facile Access of PE Elastomers with Exceptional Material Properties

For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).

PEBAX^(TM)-Silanized Al_(2)O_(3) Composite,Synthesis and Characterization

Alumina nanoparticles were dispersed in poly(amide 12-b-tetramethylene oxide) copolymer through extrusion. The alumina particles were functionalized with 3-(2 trimethoxysilylethyl) cyclohexene oxide. The following PEBAX TM/ Al2O 3 proportions were prepared: 0.1, 1.0, 5.0, and 10.0% w/w. The thermal stabiity of the nanocomposites was evalu- ated by thermograviemtric analysis under N2 and was comparable to the neat PEBAXTM polymer. The thermo-oxidative degradation of the polymeric matrix by oxygen was strongly hindered by the functionalized alumina. The rule of mixture would predict that the thermal degradation should be strongly dominated by PEBAXTM matrix. Therefore, the physical mixture of PEBAXTM and silanized alumina should be almost as stable as pure PEBAXTM. However, the experimental results suggest that the nanocomposites are more stable than the mixture of their components. This stabilization effect is evident in the temperature range between 300?C and 400?C, in which the degradation of the PA12 block takes place.

In situ polymerization preparation and mechanical properties of nanocomposites based on PA10T/10I-block-PEG copolymer and graphene oxide

Poly(decamethylene terephthalamide/decamethylene isophthalamide)-block-polyvinyl alcoho)(PA10 T/10 IPEG) copolymer/graphene oxide(GO) composites were prepared via in-situ melt polymerization and two different nano-filler addition approaches were compared. The relationship between the micro-structure and performance of the elastomer composites prepared by one-step and two-step methods was explored. The results show that the two-step method significantly promoted the dispersion of the GO in a polymer matrix, and facilitated the grafting of more hard molecular chains. Thus, the elastic modulus and tensile strength of the nanocomposite have been significantly improved by the presence of GO. This was because of the strong interaction between the functional groups on the surface of the GO and the hard molecular chains. This would be also be favorable to load transfer across the interface. Additionally, the elongation at the break of composites increased by 10% with the addition of a small amount of GO(0.2% wt). This is because hard domains tend to be enriched on the surface of GO in composites and act as a lubricating layer at the interface between the GO and matrix, leading to increased deformation ability. This work provides an effective strategy to prepare elastomer composites with high strength and toughness.

Experimental and Performance Analyses on Elastomer-Strengthened Polyethylene Terephthalate/Glass Fiber Blends

Ethylene-methacrylate-glycidyl(EMG)copolymer is employed to strengthen polyethylene terephthalate(PET)/glass fiber(GF)blends.This paper starts from investigating the effects of various EMG contents on mechanical properties,thermal properties and fractured surface morphology of PET/GF blends.All of the above-mentioned properties own extreme limits of EMG concentration.The crystallization ability of the blends increases with an increment in EMG content,whereas the crystallinity keeps stable at a relatively high level of 0-20 wt.%EMG loading.The tension,bending and impact properties of PET blends are enhanced with the addition of a self-made three-dimensional hierarchical porous carbon sponge(3DC)based on an optimal additive amount.Results indicate that EMG possesses the capabilities of increasing the toughness of PET/GF blends remarkably and transforming the blends from brittle fracture to tough fracture.According to the results,the blends exhibit the best overall properties as the content of EMG reaches 10-15 wt.%.

Boosting fire safety and mechanical performance of thermoplastic polyurethane by the face-to-face two-dimensional phosphorene/MXene architecture

Black phosphorus(BP), as one of the most promising fillers for flame retarding polymer, has been seriously limited in practical application, due to the agglomeration and poor structural stability challenges.Here, the BP was modified by MXene and polydopamine(PDA) via ultrasonication and dopamine modification strategy to improve the structural stability and dispersibility in the matrix. Then, the obtained(BP-MXene@PDA) nanohybrid was employed to promote the mechanical performance, thermal stability,and flame retardancy of thermoplastic polyurethane elastomer(TPU). The resultant TPU composite containing 2 wt.% of BP1-MXene2@PDA showed a 19.2% improvement in the tensile strength and a 13.8%increase in the elongation at break compared to those of the pure TPU. The thermogravimetric analysis suggested that BP-MXene@PDA clearly enhances the thermal stability of TPU composites. Furthermore,the introduction of the BP-MXene@PDA nanohybrids could considerably improve the flame retardancy of TPU composite, i.e., 64.2% and 27.3% decrease in peak heat release rate and total heat release, respectively. The flame-retardant mechanisms of TPU/BP-MXene@PDA in the gas phase and condensed phase were investigated systematically. This work provides a novel strategy to simultaneously enhance the fire safety and mechanical properties of TPU, thus expanding its industrial applications.

Copolymerization of 1-butene and 1-hexene with supported titanium catalyst

With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversion,catalyst efficiency(CE),intrinsic viscosity([g])and insoluble content were studied.The copolymer was analyzed with Fourier transform-infrared(FTIR)and nuclear magnetic resonance(1H-NMR).Results showed that the optimal polymerization conditions were:He/Bt=0.25,temperature 40℃–50℃,Al/Ti=400–500,Ti/(Bt+He)=3x10-5-4x10-5,time 4 h.Intrinsic viscosity was found to increase with increasing Ti/(Bt+He)and decreasing Al/Ti and polymerization temperature.When the molar content of He,Al/Ti and polymerization temperature increased,the insoluble content in CH2Cl2 of copolymers decreased.When Ti/(Bt+He)and reaction time increased,the insoluble con-tent in CH2Cl2 of copolymers also increased.The crystal-lization and stereoregularity of poly(1-butene)decreased with the addition of He.