scholarly journals Effect of GNPs on the Piezoresistive, Electrical and Mechanical Properties of PHA and PLA Films

Fibers ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 86
Author(s):  
Gonzalo Mármol ◽  
Usha Kiran Sanivada ◽  
Raul Fangueiro

Sustainability has become the primary focus for researchers lately. Biopolymers such as polyhydroxyalkanoate (PHA) and polylactic acid (PLA) are biocompatible and biodegradable. Introducing piezoresistive response in the films produced by PLA and PHA by adding nanoparticles can be interesting. Hence, a study was performed to evaluate the mechanical, electrical and piezoresistive response of films made from PHA and PLA. The films were produced by solvent casting, and they were reinforced with graphene nanoplatelets (GNPs) at different nanoparticle concentrations (from 0.15 to 15 wt.%). Moreover, cellulose nanocrystals (CNC) as reinforcing elements and polyethylene glycol (PEG) as plasticizers were added. After the assessment of the nanoparticle distribution, the films were subjected to tests such as tensile, electrical conductivity and piezoresistive response. The dispersion was found to be good in PLA films and there exist some agglomerations in PHA films. The results suggested that the incorporation of GNPs enhanced the mechanical properties until 0.75 wt.% and they reduced thereon. The addition of 1% CNCs and 20% PEG in 15 wt.% GNPs’ tensile values deteriorated further. The PHA films showed better electrical conductivity compared to the PLA films for the same GNPs wt.%. Gauge factor (GF) values of 6.30 and 4.31 were obtained for PHA and PLA, respectively.

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2189
Author(s):  
Pedro Pereira ◽  
Diana P. Ferreira ◽  
Joana C. Araújo ◽  
Armando Ferreira ◽  
Raul Fangueiro

Graphene and its derivatives have shown outstanding potential in many fields and textile/composites industry are not an exception. Giving their extraordinary properties, Graphene Nanoplatelets (GNPs) are excellent candidates for providing new functionalities to fibers and composites. In this work, natural fabrics (flax) were functionalized with chitosan (CS) based polymeric formulations of GNPs to develop fibrous systems with electrical properties as well as other functionalities. One of the greatest disadvantages of using carbon-based materials for fabrics’ impregnation is their difficult dispersion. Therefore, several polymers were used as matrices, binding and dispersive agents including chitosan, polyethylene glycol (PEG), and glycerol. All the systems were characterized using several techniques that demonstrated the presence and incorporation of the GNPs onto the composites. Besides their characterization, considering their use as smart materials for monitoring and sensing applications, electrical properties were also evaluated. The highest value obtained for electrical conductivity was 0.04 S m−1 using 2% of GNPs. Furthermore, piezoresistive behavior was observed with Gauge Factor (GF) of 1.89 using 0.5% GNPs. Additionally, UV (ultraviolet) protection ability and hydrophobicity were analyzed, confirming the multifunctional behavior of the developed systems extending their potential of application in several areas.


2019 ◽  
Vol 136 (26) ◽  
pp. 47709 ◽  
Author(s):  
Haibo Long ◽  
Zhiqiang Wu ◽  
Qianqian Dong ◽  
Yuting Shen ◽  
Wuyi Zhou ◽  
...  

Proceedings ◽  
2019 ◽  
Vol 26 (1) ◽  
pp. 18
Author(s):  
Bouamer ◽  
Benrekaa ◽  
Younes

In this study, granulated polylactic acid and ZnO, SiO2 and Al2O3 powders were mixed to form PLA/ZnO and PLA/ZnO SiO2 Al2O3 composites with different concentrations using a solvent casting method. [...]


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jose Luis Orellana ◽  
Derek Wichhart ◽  
Christopher L. Kitchens

The addition of surface-modified cellulose nanocrystals (CNCs) to polymeric matrices can lead to an enhancement of the mechanical and optical properties of host polymers. The use of surfactants can provide an easy and effective way to change the CNC functionality and to evaluate the effects of surface chemistry in the reinforcement mechanisms. In this work, CNCs were solution blended with polylactic acid (PLA) and melt extruded into films. The PLA toughness increased from 1.70 MJ/m3to 2.74 MJ/m3, a 61% increase, with the addition of 1% of decylamine-modified CNCs without a decrease of the tensile strength or modulus. In this work, we investigated the use of two surfactants, decylamine and cetyltrimethylammonium bromide, to enhance CNC compatibility with the hydrophobic PLA matrix. Decylamine at 1.0 wt.% with respect to CNC loading was found to significantly enhance CNC compatibility and property enhancement. The low concentration of surfactant is notable, as other works typically use significantly higher loadings for CNC incorporation and property enhancement. At high CNC concentrations, mechanical properties decreased but the aligned assembly of the CNCs provided intricate colors to the films when observed between crossed polars. The alignment and nanoscale structure of CNCs within the films play an important role in the properties obtained.


2019 ◽  
Vol 1 (7) ◽  
pp. 2510-2517 ◽  
Author(s):  
Weiheng Xu ◽  
Sayli Jambhulkar ◽  
Rahul Verma ◽  
Rahul Franklin ◽  
Dharneedar Ravichandran ◽  
...  

Exfoliated and aligned continuous graphene nanoplatelet channels with enhanced mechanical properties and superior electrical conductivity.


2010 ◽  
Vol 7 (1) ◽  
pp. 105-110 ◽  
Author(s):  
M. Banimahd Keivani ◽  
K. Zare ◽  
M. Aghaie ◽  
H. Aghaie ◽  
M. Monajjemi

Polyaniline (PAn) was prepared chemically in the presence of bronsted acid from aqueous solutions. Polyaniline- nylon 6 composite (termed as PAn/Ny6) prepared via solvent casting method. The preparation conditions were optimized with regard to the mechanical properties of the polymer composite. It was found that the molar ratio of PAn to nylon have the greatest effect in determining the mechanical properties of polymer composite. Electrical conductivity was measured using standard method of four point probe. Spectrophotometric analysis (UV-Vis) was used for investigation of the effect of thermal treatment on polyaniline and it’s composite.


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