Preparation and characterization of PLA foam chain extended through grafting octa(epoxycyclohexyl) POSS onto carbon nanotubes

2020 ◽  
Vol 39 (3) ◽  
pp. 117-138
Author(s):  
Wei Liu ◽  
Xunxian Zhu ◽  
Hongxiang Gao ◽  
Xiangdong Su ◽  
Xian Wu

Improving foamability of poly (lactic acid) (PLA) resin is a key issue for its critical foaming applications with high-performance and ultralow density. However, owing to the rheological nature of linear PLA chain structure with relatively low molecular weight, the overall foamability of PLA resin cannot meet the processing requirements of foaming purpose. Here, we describe a simple and versatile technique to prepare high foamability PLA resin by inducing chain extender through grafting octa(epoxycyclohexyl) polyhedral oligomeric silsesquioxanes (POSS) on carbon nanotubes (CNT). After the orderly assemble of the two nanoparticles, an obvious increase in melt elasticity of PLA is observed. The enhanced melt elasticity of PLA had a significant effect on controlling subsequent foaming behavior. Thus, a homogeneous and finer cellular morphology of PLA rigid foam was obtained with a proper content of CNT-POSS. Eventually, the expansion ratio of chain-extended PLA foam was 13 times higher than that of unmodified PLA foam. The proposed design methodology will potentially pave a way for designing and preparing high-performance PLA rigid foam products.

2017 ◽  
Vol 36 (2) ◽  
pp. 75-96 ◽  
Author(s):  
Wei Liu ◽  
Peng Chen ◽  
Xiangdong Wang ◽  
Fuchun Wang ◽  
Yujiao Wu

The effect of a bio-based macromolecule, poly(butylene adipate-co-terephthalate) (PBAT), on the crystallization and foaming behavior of poly(lactic acid) (PLA) was evaluated. The crystallization kinetics results show that the addition of PBAT improved the crystallization of PLA by increasing the overall crystallinity and enhancing the crystal morphology of PLA. The massive crystallization zones may have prevented the escape of foaming gases to the surrounding area; the expansion ratio of the PLA foams increased from 4.87 to 10.94. Thus, a novel macromolecular crystallization nucleating agent for PLA was developed; the effect of the crystallization of PLA on its foaming behavior was also investigated. A high expansion ratio and finer cellular structure of PLA foam were obtained by optimizing the PBAT content.


2018 ◽  
Vol 37 (4-6) ◽  
pp. 189-205 ◽  
Author(s):  
Liu Wei ◽  
He Shicheng ◽  
Zhou Hongfu

High-performance poly(lactic acid) (PLA) foam has been recognized as a promising material because of its biodegradability. However, low flexibility and foamability of PLAs has limited its use in different fields. In this study, a blend-toughening technology was used to toughen PLA and prepare flexible foams. The mechanical properties of PLA blends were evaluated, and the cellular structure of these foaming blends was characterized. The results show that the blending components significantly affected the overall mechanical properties and foaming behavior of PLA. The toughness of PLA was enhanced by adding poly(butylene adipate- co-terephthalate) (PBAT) and rigid particles. The rheological behavior of PLA was also affected by adding PBAT. Therefore, the cellular structure of the PLA foams was affected. A constitutive model was also used to fit the experimental results of the compression property of the PLA foam.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jae-Won Lee ◽  
Joon Young Cho ◽  
Mi Jeong Kim ◽  
Jung Hoon Kim ◽  
Jong Hwan Park ◽  
...  

AbstractSoft electronic devices that are bendable and stretchable require stretchable electric or electronic components. Nanostructured conducting materials or soft conducting polymers are one of the most promising fillers to achieve high performance and durability. Here, we report silver nanoparticles (AgNPs) embedded with single-walled carbon nanotubes (SWCNTs) synthesized in aqueous solutions at room temperature, using NaBH4 as a reducing agent in the presence of highly oxidized SWCNTs as efficient nucleation agents. Elastic composite films composed of the AgNPs-embedded SWCNTs, Ag flake, and polydimethylsiloxane are irradiated with radiation from a Xenon flash lamp within a time interval of one second for efficient sintering of conductive fillers. Under high irradiation energy, the stretchable electrodes are created with a maximum conductivity of 4,907 S cm−1 and a highly stretchable stability of over 10,000 cycles under a 20% strain. Moreover, under a low irradiation energy, strain sensors with a gauge factor of 76 under a 20% strain and 5.4 under a 5% strain are fabricated. For practical demonstration, the fabricated stretchable electrode and strain sensor are attached to a human finger for detecting the motions of the finger.


2021 ◽  
Author(s):  
Mingjie Li ◽  
Xuan Zheng ◽  
Xiang Li ◽  
Youjun Yu ◽  
Jinlong Jiang

Recently, transition metal selenides have been investigated extensively as promising electrode materials for high-performance supercapacitors. Herein, the multi-component CoSe2/CNTs@g-C3N4 composites are prepared using a two-step hydrothermal method by incorporating one-dimensional...


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