Crystalline,Rheological and Mechanical Enhancement in PBAT/PPC/Silica Nanocomposites with Double Percolation Network

Nanocomposites of blends of biodegradable poly(butylene adipate-co-terephthalate)(PBAT)and sustainable poly(propylene carbonate)(PPC)with nanosilica were prepared by melt compounding method.PBAT/PPC blend was partially miscible system with sea-island structure,and nanosilica particles were selectively dispersed in the continuous phase PBAT matrix to form the double percolation network.The introduction of nanosilica into PBAT/PPC blend reduced the size of dispersed PPC phase,promoted the crystallization of PBAT in the nanocomposites,and increased the storage modulus of the nanocomposites.The study of rheological behaviors indicated that the double percolation network was formed at the nanosilica loading of 5 wt%,as a result,the nanocomposites exhibited the solid-like viscoelastic behavior and their relaxation time was extended.With the increase of the nanosilica content,the PBAT/PPC/silica nanocomposites displayed increased Young's modulus and yield strength.

High-performance fiber strain sensor of carbon nanotube/thermoplastic polyurethane@styrene butadiene styrene with a double percolated structure

In this work,a high-performance fiber strain sensor is fabricated by constructing a double percolated structure,consisting of carbon nanotube(CNT)/thermoplastic polyurethane(TPU)continuous phase and styrene butadiene styrene(SBS)phase,incompatible with TPU(CNT/TPU@SBS).Compared with other similar fiber strain sensor systems without double percolated structure,the CNT/TPU@SBS sensor achieves a lower percolation threshold(0.38 wt.%)and higher electrical conductivity.The conductivity of 1%-CNT/TPU@SBS(4.12×10^(-3) S·m^(-1))is two orders of magnitude higher than that of 1%-CNT/TPU(3.17×10^(-5) S·m^(-1))at the same CNT loading of 1 wt.%.Due to double percolated structure,the 1%-CNT/TPU@SBS sensor exhibits a wide strain detection range(0.2%-100%)and an ultra-high sensitivity(maximum gauge factor(GF)is 32411 at 100%strain).Besides,the 1%-CNT/TPU@SBS sensor shows a high linearity(R^(2)=0.97)at 0%-20%strain,relatively fast response time(214 ms),and stability(500 loading/unloading cycles).The designed sensor can efficiently monitor physiological signals and movements and identify load distribution after being woven into a sensor array,showing broad application prospects in wearable electronics.

Conductivity of Poly(methyl methacrylate)/Polystyrene/Carbon Black and Poly(ethyl methacrylate)/Polystyrene/Carbon Black Ternary Composite Films

Poly(methyl methacrylate)(PMMA)/polystyrene(PS)/carbon black(CB)and poly(ethyl methacrylate)(PEMA)/PS/CB ternary composite films were obtained using solution casting technique to investigate double percolation effect.In both PMMA/PS/CB and PEMA/PS/CB ternary composite films,the CB particles prefer to locate into PS phase based on the results of calculating wetting coefficient,which is also confirmed by SEM images.The conductivity of the films was investigated,and the percolation threshold(￠c)of both ternary composite films with different polymer blend ratios was determined by fitting the McLachlan GEM equation.Conductivity of PMMA/PS/CB ternary composite films showed a typical double percolation effect.However,due to the double emulsion structure of PEMA/PS polymer blends,the PEMA/PS/CB ternary composite films(PEMA/PS=50/50)showed a higher￠c,even CB only located in PS phase,which conflicts with the double percolation effect.A schematic diagram combined with SEM images was proposed to explain this phenomenon.