scholarly journals Poly(3-hydroxybutyrate) Modified by Plasma and TEMPO-Oxidized Celluloses

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1510 ◽  
Author(s):  
Denis Mihaela Panaitescu ◽  
Sorin Vizireanu ◽  
Sergiu Alexandru Stoian ◽  
Cristian-Andi Nicolae ◽  
Augusta Raluca Gabor ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Thermal And Mechanical Properties ◽  
Tempo Oxidation ◽  
Water Suspensions ◽  
Shaped Tube ◽  
Surface Modified ◽  
Mediated Oxidation ◽  
Thermal Stability Of ◽  
Modified Cellulose

Microcrystalline cellulose (MCC) was surface modified by two approaches, namely a plasma treatment in liquid using a Y-shaped tube for oxygen flow (MCC-P) and a TEMPO mediated oxidation (MCC-T). Both treatments led to the surface functionalization of cellulose as illustrated by FTIR and XPS results. However, TEMPO oxidation had a much stronger oxidizing effect, leading to a decrease of the thermal stability of MCC by 80 °C. Plasma and TEMPO modified celluloses were incorporated in a poly(3-hydroxybutyrate) (PHB) matrix and they influenced the morphology, thermal, and mechanical properties of the composites (PHB-MCC-P and PHB-MCC-T) differently. However, both treatments were efficient in improving the fiber–polymer interface and the mechanical properties, with an increase of the storage modulus of composites by 184% for PHB-MCC-P and 167% for PHB-MCC-T at room temperature. The highest increase of the mechanical properties was observed in the composite containing plasma modified cellulose although TEMPO oxidation induced a much stronger surface modification of cellulose. This was due to the adverse effect of more advanced degradation in this last case. The results showed that Y-shaped plasma jet oxidation of cellulose water suspensions is a simple and cheap treatment and a promising method of cellulose functionalization for PHB and other biopolymer reinforcements.

Thermal Stability of PECS-Compacted Cu-Composites

2012 ◽  
Vol 527 ◽  
pp. 113-118 ◽  
Author(s):  
Riina Ritasalo ◽  
Ulla Kanerva ◽  
Simo Pekka Hannula
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Room Temperature ◽  
Temperature Stability ◽  
Thermal And Mechanical Properties ◽  
High Temperature Stability ◽  
Composite Powders ◽  
High Quality ◽  
Pulsed Electric Current ◽  
Thermal Stability Of

In this paper pulsed electric current sintering (PECS) is applied for submicron-sized copper (sm-Cu) based composite-powders aiming to produce MMC’s with higher strength and better temperature stability than reference sm-Cu. Incorporation of cuprite (Cu2O), alumina (Al2O3), titaniumdiboride (TiB2) and nano- and submicronsized diamonds (ND’s and SMD’s) improved noticeably the room temperature mechanical properties and the high-temperature stability of copper the effects becoming more noticeable with smaller dispersion size and higher amount of reinforcement. The hardness increment was at highest, when using ND’s or Al2O3. E.g., the microhardness for the reference sm-Cu sample and Cu with 3 vol.% ND’s, 6 vol.% ND’s and 2.5 vol.% Al2O3 were 1.02, 1.43, 1.77 and 1.58 GPa, respectively. Similar trend was noted also in the case of thermal stability and CTE. The study shows that Cu-ND, Cu-SMD and Cu-Cu2O are suitable for use at moderate temperatures around 623 - 673 K, whereas Cu-Al2O3 and Cu-TiB2 are suitable above 1023 K. In conclusion, PECS is suitable method to produce high quality Cu-composites having superior thermal and mechanical properties compared to those of sm-Cu.

scholarly journals Effect of Organic Modifier Types on the Physical–Mechanical Properties and Overall Migration of Post-Consumer Polypropylene/Clay Nanocomposites for Food Packaging

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1502
Author(s):  
Eliezer Velásquez ◽  
Sebastián Espinoza ◽  
Ximena Valenzuela ◽  
Luan Garrido ◽  
María José Galotto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Food Packaging ◽  
Clay Nanocomposites ◽  
Organic Modifier ◽  
Thermal And Mechanical Properties ◽  
Chemical Safety ◽  
Elongation At Break ◽  
Fatty Food ◽  
Recycled Plastics ◽  
Thermal Stability Of

The deterioration of the physical–mechanical properties and loss of the chemical safety of plastics after consumption are topics of concern for food packaging applications. Incorporating nanoclays is an alternative to improve the performance of recycled plastics. However, properties and overall migration from polymer/clay nanocomposites to food require to be evaluated case-by-case. This work aimed to investigate the effect of organic modifier types of clays on the structural, thermal and mechanical properties and the overall migration of nanocomposites based on 50/50 virgin and recycled post-consumer polypropylene blend (VPP/RPP) and organoclays for food packaging applications. The clay with the most hydrophobic organic modifier caused higher thermal stability of the nanocomposites and greater intercalation of polypropylene between clay mineral layers but increased the overall migration to a fatty food simulant. This migration value was higher from the 50/50 VPP/RPP film than from VPP. Nonetheless, clays reduced the migration and even more when the clay had greater hydrophilicity because of lower interactions between the nanocomposite and the fatty simulant. Conversely, nanocomposites and VPP/RPP control films exhibited low migration values in the acid and non-acid food simulants. Regarding tensile parameters, elongation at break values of PP film significantly increased with RPP addition, but the incorporation of organoclays reduced its ductility to values closer to the VPP.

Effect of Cellulose Functionalization on Thermal and Mechanical Properties of Epoxy Resin

2017 ◽  
Vol 757 ◽  
pp. 62-67 ◽  
Author(s):  
Kritsanachai Leelachai ◽  
Supissara Ruksanak ◽  
Tarakol Hongkeab ◽  
Supakeat Kambutong ◽  
Raymond A. Pearson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Diglycidyl Ether ◽  
Cellulose Content ◽  
Thermal And Mechanical Properties ◽  
Chemical Surface ◽  
Pull Out ◽  
Fiber Bridging ◽  
Surface Modified ◽  
Modified Epoxy

In this study, diglycidyl ether of bisphenol A (DGEBA) cured cycloaliphatic polyamine was modified with functionalized celluloses for improved thermal and mechanical properties. Three different types of surface-modified cellulose, polyacrylamide-g-cellulose (PGC), aminopropoxysilane-g-cellulose (SGC), and carboxymethyl cellulose (CMC), were investigated and used as reinforcing agents in epoxy resins. The storage modulus of these modified epoxy systems was found to significantly increase with addition of cellulose fillers (up to 1 wt. % cellulose content). An improved fracture toughness (KIC) was also observed with increasing cellulose loading content with PGC and SGC. Among the surface-modified celluloses, epoxy modified with SGC was found to have the highest fracture toughness followed by PGC and CMC at 1.0 wt.% cellulose addition due to the chemical surface compatibility. The toughening mechanisms of the cellulose/epoxy composites, measured by scanning electron microscopy (SEM), revealed that fiber-debonding, fiber-bridging, and fiber-pull out were responsible for increased toughness.

Thermal and mechanical properties of polymethyl mathacrylate reinforced by polyhedral oligomeric silsesquioxane

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Benghong Yang ◽  
Meng Li ◽  
Bangping Song ◽  
Yun Wu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Thermal And Mechanical Properties ◽  
Sem Images ◽  
Pmma Matrix ◽  
Oligomeric Silsesquioxane ◽  
Tga And Dsc ◽  
Thermal Stability Of

AbstractA series of Inorganic/organic nanocomposites were prepared by blending cage-like carboxyl-bearing polyhedral oligomeric silsesquioxane (carboxyl-POSS) with polymethyl mathacrylate (PMMA) in THF solvent. FTIR and 29Si-NMR were employed to characterize the structures of the nanocomposites. SEM images showed that the as-prepared films were smooth and no aggregation of carboxyl-POSS was observed. TGA and DSC results showed that the incorporation of small amount of nanosize carboxyl-POSS enhanced the thermal stability of PMMA. When 1.0 wt% of carboxyl-POSS was incorporated into PMMA matrix, the Tg and Td increased by 16.9 °C and 21.0 °C, respectively. However, higher POSS contents (>1.0 wt%) would deteriorate the thermal and mechanical properties of the nanocomposites.

Nafion – Azole Composite Membranes for High Temperature PEMFC

2014 ◽  
Vol 783-786 ◽  
pp. 1692-1697
Author(s):  
Je Deok Kim ◽  
Mun Suk Jun
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Temperature ◽  
Proton Conductivity ◽  
Composite Membrane ◽  
Room Temperature ◽  
Composite Membranes ◽  
Thermal And Mechanical Properties ◽  
High Proton Conductivity ◽  
High Proton

Nafion-azole (benzimidazole, 1,2,4-triazole, 1,2,3-triazole) composite membranes were prepared by room temperature and autoclave solution processing for high temperature (above 100 °C) PEMFC. Among the various Nafion – azole composite membranes, Nafion – 1,2,3-triazole membrane showed excellent flexibility, thermal stability, and homogeneous structure. Nafion – 1,2,4-triazole composite membrane had high thermal and mechanical properties, and also showed high proton conductivity of 0.02 S/cm at the temperature of 160 °C under dry (N2) condition.

scholarly journals Trace Scandium addition on the strength and thermal stability of TiB2 particles reinforced Al-4.5 Cu composites

2021 ◽  
Vol 2133 (1) ◽  
pp. 012018
Author(s):  
Yunliang Zhang ◽  
Wentao Yu ◽  
Xinliang Wang ◽  
Yanqing Xue
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Fracture Strain ◽  
Copper Matrix ◽  
Homogeneous Distribution ◽  
Matrix Composites ◽  
Aluminium Copper ◽  
Sc Addition ◽  
Tib2 Particles ◽  
Thermal Stability Of

Abstract Strategies employed for developing ultrahigh strength and scalable ductile particles reinforced aluminium-copper matrix composites (AMCs) are highly desirable and grandly challenging. In the present paper, the Scandium (Sc) micro-alloying TiB2 particles reinforced Al-4.5 Cu composites were successfully fabricated by the optimized salt-metal reaction method. The observed microstructures displayed that Sc addition could remarkably ameliorate the dispersion of TiB2 particles, enlarge equiaxed α-Al grain zone and refine the grains on the basis of TiB2 heterogeneous nucleation. In particular, for the 0.4 wt.% Sc microalloyed 5%TiB2/Al-4.5Cu composites, more than a 20 %, 87 %, and 118 % increase in the ultimate tensile strength (UTS), fracture strain elongation (%) and microhardness (HV), respectively were found with respect to the 3 %TiB2/Al-4.5Cu composites at room temperature (298K). The improved mechanical properties of strength-ductility synergy were mainly thanks to the homogeneous distribution of TiB2 particles and modification of Al2Cu phase. Moreover, proper Sc also enhanced the elevated-temperature mechanical properties of the composites with the aid of the accelerated precipitation of θ′ phase and much lower coarsens rate.

Study on structure and properties of biodegradable PLA/PBAT/organic-modified MMT nanocomposites

2019 ◽  
pp. 089270571989090 ◽  
Author(s):  
Hezhi He ◽  
Bida Liu ◽  
Bin Xue ◽  
He Zhang
Keyword(s):  
Mechanical Properties ◽  
Poly Lactic Acid ◽  
Esterification Reaction ◽  
Melt Blending ◽  
Structure And Properties ◽  
Thermal And Mechanical Properties ◽  
Modified Montmorillonite ◽  
Structure Morphology ◽  
Reinforcing Effects ◽  
Thermal Stability Of

Biodegradable polymer blends were prepared by melt blending poly(lactic acid) (PLA), poly(butylene adipate- co-terephthalate) (PBAT), and organic-modified montmorillonite (MMT). The effects of MMT on the structure, morphology, thermal, and mechanical properties of the blends were thoroughly investigated. The results revealed that MMT was preferable to localize on the interface of PLA and PBAT and esterification reaction took place between organic-modified MMT and PLA/PBAT. MMT enhanced the compatibility of PLA and PBAT, accelerated crystallization, and improved the thermal stability of PLA and PBAT. In addition, MMT illustrated the reinforcing effects on PLA and PBAT in their tensile strength, especially for PBAT.

Morphological, Thermal and Mechanical Properties of Poly(Lactic Acid)/Cellulose/ Nano-Clay Composite

2020 ◽  
Vol 856 ◽  
pp. 331-338
Author(s):  
Sirisart Ouajai ◽  
Suttinun Phongtamrug
Keyword(s):  
Mechanical Properties ◽  
Flexural Modulus ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Nano Clay ◽  
Twin Screw ◽  
Modified Cellulose

This research has focused on the effect of modified cellulose and clay on the thermal and mechanical properties of PLA bio-nanocomposite. Cellulose was chemically modified with silane coupling agent in order to enhance compatiblization with PLA. Successful modification was confirmed by Fourier Transform Infrared Spectroscopy and EDX-SEM. PLA was compounded with various amounts and ratios of the modified cellulose and clay by a twin-screw extruder. Thermal properties of the bio-nanocomposites were characterized by Thermogravimetric Analysis and Differential Scanning Calorimetry. Glass transition temperature of the bio-nanocomposite slightly decreased whereas melting temperature remained constant when the amount of both fillers was increased. In addition, crystallization behaviour of PLA has been influenced by the type and amount of the fillers. Clay showed a greater effect on the crystallization of PLA than the modified cellulose and unmodified one, respectively. The flexural modulus of the composite containing equal amount between clay and cellulose was increased with an increasing in fillers contents. But the flexural and impact strength of composite were gradually decreased with an increase in fillers contents. Variation of clay and cellulose ratio resulted in the change of mechanical properties. The composite containing higher ratio between clay:cellulose or cellulose:clay showed a better mechnical properties comparing to the ratio of clay:cellulose equal to 1:1.

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