scholarly journals Reaction Mechanism and Mechanical Property Improvement of Poly(Lactic Acid) Reactive Blending with Epoxy Resin

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2429
Author(s):  
Krittameth Kiatiporntipthak ◽  
Nanthicha Thajai ◽  
Thidarat Kanthiya ◽  
Pornchai Rachtanapun ◽  
Noppol Leksawasdi ◽  
...  

Polylactic acid (PLA) was melt-blended with epoxy resin to study the effects of the reaction on the mechanical and thermal properties of the PLA. The addition of 0.5% (wt/wt) epoxy to PLA increased the maximum tensile strength of PLA (57.5 MPa) to 67 MPa, whereas the 20% epoxy improved the elongation at break to 12%, due to crosslinking caused by the epoxy reaction. The morphology of the PLA/epoxy blends showed epoxy nanoparticle dispersion in the PLA matrix that presented a smooth fracture surface with a high epoxy content. The glass transition temperature of PLA decreased with an increasing epoxy content owing to the partial miscibility between PLA and the epoxy resin. The Vicat softening temperature of the PLA was 59 °C and increased to 64.6 °C for 0.5% epoxy. NMR confirmed the reaction between the -COOH groups of PLA and the epoxy groups of the epoxy resin. This reaction, and partial miscibility of the PLA/epoxy blend, improved the interfacial crosslinking, morphology, thermal properties, and mechanical properties of the blends.

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 461 ◽  
Author(s):  
Zeyu Sun ◽  
Lei Xu ◽  
Zhengguo Chen ◽  
Yuhao Wang ◽  
Rogers Tusiime ◽  
...  

Efficient enhancement of the toughness of epoxy resins has been a bottleneck for expanding their suitability for advanced applications. Here, polysulfone (PSF) was adopted to toughen and modify the epoxy. The influences of PSF on the mechanical and thermal properties of the epoxy resin were systematically studied by optical microscopy, Fourier transform infrared spectrometer (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analyzer (TG), dynamic mechanical thermal analyzer (DMA), mechanical tests and scanning electron microscope (SEM). The dissolution experimental results showed that PSF presents a good compatibility with the epoxy resin and could be well dissolved under controlled conditions. The introduction of PSF was found to promote the curing reaction of the epoxy resin without participating in the curing reaction and changing the curing mechanism as revealed by the FT-IR and DSC studies. The mechanical properties of PSF/epoxy resin blends showed that the fracture toughness and impact strength were significantly improved, which could be attributed to the bicontinuous phase structure of PSF/epoxy blends. Representative phase structures resulted from the reaction induced phase separation process were clearly observed in the PSF/epoxy blends during the curing process of epoxy resin, which presented dispersed particles, bicontinuous and phase inverted structures with the increase of the PSF content. Our work further confirmed that the thermal stability of the PSF/epoxy blends was slightly increased compared to that of the pure epoxy resin, mainly due to the good heat resistance of the PSF component.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chaitra Venkatesh ◽  
Yuanyuan Chen ◽  
Zhi Cao ◽  
Shane Brennan ◽  
Ian Major ◽  
...  

Abstract Poly (lactic acid)/halloysite nanotube (PLA/HNT) nanocomposites have been studied extensively over the past few years owing to the interesting properties of the polymer, PLA, and the nanoclay, HNT, individually and as composites. In this paper, the influence of the screw speed during extrusion was investigated and was found to have a significant impact on the mechanical and thermal performance of the extruded PLA/HNT nanocomposites. To determine the effect of screw speed on PLA/HNT nanocomposites, 5 and 10 wt% of HNTs were blended into the PLA matrix through compounding at screw speeds of 40, 80, and 140 rpm. Virgin PLA was compounded for comparison. The resultant polymer melt was quench cooled onto a calendar system to produce composite films which were assessed for mechanical, thermal, chemical, and surface properties. Results illustrate that in comparison to 40 and 80 rpm, the virgin PLA when compounded at 140 rpm, indicated a significant increase in the mechanical properties. The PLA/HNT 5 wt% nanocomposite compounded at 140 rpm showed significant improvement in the dispersion of HNTs in the PLA matrix which in turn enhanced the mechanical and thermal properties. This can be attributed to the increased melt shear at higher screw speeds.


2019 ◽  
Vol 225 ◽  
pp. 239-246 ◽  
Author(s):  
Ahmer Hussain Shah ◽  
Xiao Li ◽  
Xiaodong Xu ◽  
Abdul Qadeer Dayo ◽  
Wen-bin Liu ◽  
...  

2020 ◽  
Vol 981 ◽  
pp. 138-143
Author(s):  
Esa N. Shohih ◽  
Mujtahid Kaavessina ◽  
Henry A. S. Lomi ◽  
Betha P. Pratiwi ◽  
Sperisa Distantina ◽  
...  

Conductive polymer composites (CPCs) have attracted great attention of researchers due to their enhanced properties such as an adjustable electrical conductivity, good processability, good mechanical and thermal properties, etc. CPCs had many potencies for wider application in electronic devices. Poly (lactic acid) or PLA is one of the interesting polymers used in the developing of these new important materials. PLA properties are comparable to the synthetic petroleum-based polymers such as polyethylene terephthalate (PET), polypropylene (PP), etc. This research focuses on studying the rheological and thermal properties of PLA/micro-graphite as a conductive polymer composite which adjustable its electrical conductivity. In this study, the PLA/micro-graphite was prepared through solvent blending method using chloroform. The micro-graphite composition was varied from 0%, 5%, and 10 % (w/w) with different stirring time (30 and 60 minutes) and then, poured in glass mould. In the melt rheology study, the frequency sweep test showed that the complex viscosity (|η*|) of the bio-composite increased with the micro-graphite loading. The same tendency was also found in thermal property and stability. The melting temperature and thermal degradation were slightly increasing. The crystallinity of PLA was influenced by the presence of micro-graphite. In this solvent blending method, the homogeneous distribution of micro-graphite in the bio-composite required at least 60 minutes (stirred at 650 rpm and 60 °C).


2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.


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