Thermo-physical behaviors of carbon nanofiber reinforced polylactic acid

2013 ◽  
Vol 1505 ◽  
Author(s):  
Ananta Raj Adhikari ◽  
Kamal Sarkar ◽  
Karen Lozano
Keyword(s):  
Thermal Stability ◽  
Polylactic Acid ◽  
Carbon Nanofiber ◽  
Water Soluble ◽  
Steady Increase ◽  
Future Technology ◽  
Large Numbers ◽  
Stage Crystallization ◽  
Thermo Physical Properties ◽  
Thermal Stability Of

ABSTRACT:Studies have demonstrated that the reinforcement of polymeric matrices using nanofiller can results with better thermo-physical properties of polymer. Carbon nanofiber (CNF) is a unique quasi-one dimensional nanostructure with large numbers of edges and defects compared to carbon nanotube (CNT). Further the availability in large quantity along with lower cost makes them an important nanomaterial for future technology. We have previously used CNF in different thermoplastic polymers. In this study CNFs were used with water soluble thermoplastic aliphatic polyster polylactic acid (PLA) and studied their thermal and mechanical properties. Thermal analysis using Thermogravimetric Analysis showed enhanced thermal stability of the polymer at higher nanotube loading (>1 wt%) and decrease of thermal stability at higher loading (>10 wt%). Crystallization thermogram of PLA was modified heavily with the addition of nanofibers changing clearly from one stage to two stage crystallization. In addition, CNF facilitates the crystallization of PLA resulting in an increase of its crystallization. The mechanical testing showed the steady increase of modulus of the composites with the nanofiber content within the range of study which can be regarded as due to the change in interface property of the composites.

The Influence of Alkaline Treatment on Mechanical Properties and Morphology of Rice Husk Fibre Reinforced Polylactic Acid

2014 ◽  
Vol 911 ◽  
pp. 13-17 ◽  
Author(s):  
Abdullah Farah Dina ◽  
Sa’ad Siti Zaleha ◽  
Bonnia Noor Najmi ◽  
Ibrahim Nor Azowa
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Brittle Fracture ◽  
Polylactic Acid ◽  
Rice Husk ◽  
Alkaline Treatment ◽  
Distilled Water ◽  
Internal Mixer ◽  
Fesem Micrographs ◽  
Thermal Stability Of

This study focuses on the influence of surface treatment and fibre sizes on mechanical behavior, physical properties and morphology of rice husk fibre (RHF) reinforced polylactic-acid (PLA). Modified RHF was prepared by using 6w.t.% sodium hydroxide (NaOH) and distilled water. PLA composite reinforced with 25w.t.% volume fractions of modified RHF was mixed using the internal mixer and fabricated by the mini injection moulding. Tensile and flexural strength results showed that the PLA composite with 100, 200 and 500μm particles sizes of water treated fibre are much higher than those of alkaline treated. DSC measurement was performed and indicated that the Tg,Tmand ΔHmof PLA reduced after reinforcement with water treated and alkaline treated fibres. TGA results showed that the treatment reduced the thermal stability of the PLA. FESEM micrographs for flexural fractured surfaces of composites showed micro crack and pores due to brittle fracture of the PLA matrix adjacent to the fibre as a result of the brittle nature of the PLA resin.

scholarly journals Thermal Stability of Gel Foams Stabilized by Xanthan Gum, Silica Nanoparticles and Surfactants

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 179
Author(s):  
Youjie Sheng ◽  
Canbin Yan ◽  
Yang Li ◽  
Yunchuan Peng ◽  
Li Ma ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Surface Activity ◽  
Xanthan Gum ◽  
Foam Stability ◽  
Water Soluble ◽  
Water Soluble Polymer ◽  
Foaming Ability ◽  
Subtle Effect ◽  
Thermal Stability Of ◽  
Foam Drainage

The foams stabilized by nanoparticles (NPs), water-soluble polymers, and surfactants have potential application prospects in the development of new, environmentally friendly firefighting foams. In the present study, a gel foam containing a water-soluble polymer (xanthan gum, XG), hydrophilic silica NPs, hydrocarbon surfactant (SDS), and fluorocarbon surfactant (FS-50) were prepared. The surface activity, conductivity, viscosity, and foaming ability of foam dispersions were characterized. The gel foam stability under a radiation heat source and temperature distribution in the vertical foam layer were evaluated systematically. The results show that the addition of NPs and XG has a significant effect on the foaming ability, viscosity and foam thermal stability, but has a very subtle effect on the conductivity and surface activity. The foaming ability of the FS-50/SDS solution was enhanced by the addition of NPs, but decreased with increasing the XG concentration. The thermal stability of the foams stabilized by SDS/FS-50/NPs/XG increased with the addition of NPs and increasing XG concentration. Foam drainage and coarsening were significantly decelerated by the addition of NPs and XG. The slower foam drainage and coarsening are the main reason for the intensified foam thermal stability. The results obtained from this study can provide guidance for developing new firefighting foams.

scholarly journals Properties of Polylactic Acid Reinforced by Hydroxyapatite Modified Nanocellulose

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1009 ◽  
Author(s):  
Jianxiao Lu ◽  
Chuanyue Sun ◽  
Kexin Yang ◽  
Kaili Wang ◽  
Yingyi Jiang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Thermogravimetric Analysis ◽  
Thermodynamic Properties ◽  
Composite Film ◽  
Polylactic Acid ◽  
Tensile Modulus ◽  
The Poor ◽  
Thermal Stability Of

Polylactic acid (PLA) is one of the most promising bio-based materials, but its inherent hydrophobicity limits its application. Although nanocellulose (NCC) is a desirable reinforcement for PLA, the poor interface compatibility between the two has been a challenge. In this work, hydroxyapatite (HAP) modified NCC was prepared, and the obtained NCC/HAP reinforcement was used to prepare PLA/NCC-HAP composites. Different ratios of NCC to HAP were studied to explore their effects on the mechanical and thermodynamic properties of the composites. When the ratio of NCC to HAP was 30/70, the tensile strength and tensile modulus of the composite film reached 45.6 MPa and 2.34 GPa, respectively. Thermogravimetric analysis results indicate that thermal stability of the composites was significantly improved compared with pure PLA, reaching 346.6 °C. The above revelations show that NCC/HAP significantly improved the interface compatibility with PLA matrix.

Flame retardancy and thermal stability of agricultural residue fiber‐reinforced polylactic acid: A Review

2020 ◽  
Author(s):  
Vianney Andrew Yiga ◽  
Michael Lubwama ◽  
Sinja Pagel ◽  
Johannes Benz ◽  
Peter Wilberforce Olupot ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Polylactic Acid ◽  
Flame Retardancy ◽  
Fiber Reinforced ◽  
Agricultural Residue ◽  
Thermal Stability Of

Thermal stability of polypropylene/carbon nanofiber composite

2006 ◽  
Vol 100 (5) ◽  
pp. 3574-3578 ◽  
Author(s):  
Arobindo Chatterjee ◽  
B. L. Deopura
Keyword(s):  
Thermal Stability ◽  
Carbon Nanofiber ◽  
Nanofiber Composite ◽  
Thermal Stability Of

Chemical modification results in hyperactivation and thermostabilization ofFusarium solaniglucoamylase

2007 ◽  
Vol 53 (2) ◽  
pp. 177-185 ◽  
Author(s):  
Haq Nawaz Bhatti ◽  
M. Hamid Rashid ◽  
Muhammad Asgher ◽  
Rakhshanda Nawaz ◽  
A.M. Khalid ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Modification ◽  
Soluble Starch ◽  
Water Soluble ◽  
Chemically Modified ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Specificity Constant ◽  
Modified Forms ◽  
Thermal Stability Of

Chemical modification of carboxyl groups of glucoamylase from a mesophilic fungus, Fusarium solani , was carried out using ethylenediamine as nucleophile in the presence of water-soluble 1-ethyl-3(3-dimethylaminopropyl)carbodiimide. Modification brought about a dramatic enhancement of catalytic activity and thermal stability of glucoamylase. Temperature and pH optima of ethylenediamine-coupled glucoamylase (ECG) increased as compared with those of native enzyme. The specificity constant (kcat/Km) of native, ECG-2, ECG-11, and ECG-17 was 136, 173, 225, and 170, respectively, at 55 °C. The enthalpy of activation (ΔH*) and free energy of activation (ΔG*) for soluble starch hydrolysis were lower for the chemically modified forms. All of the modified forms werestable at higher temperatures and possessed high ΔG* against thermal unfolding. The effects of α-chymotrypsin and subtilisin on the modified forms were activating as compared with native. Moreover, denaturation of ECG-2, ECG-11, and ECG-17 in urea at 4 mol·L–1also showed an activation trend. A possible explanation for the thermal denaturation of native and increased thermal stability of ECG-2, ECG-11, and ECG-17 at higher temperatures is also discussed.

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