scholarly journals Synthesis and Properties of Cross-Linkable Waterborne Polyurethane/HMMM-CNT Nanocomposite

Nano Hybrids ◽  
2014 ◽  
Vol 7 ◽  
pp. 87-111
Author(s):  
Mohammad Mizanur Rahman ◽  
M. Nasiruzzaman Shaikh
Keyword(s):  
Mechanical Properties ◽  
Methoxy Group ◽  
Waterborne Polyurethane ◽  
Carboxylic Group ◽  
Acid Salt ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Methoxy Groups ◽  
Carboxylic Groups ◽  
Carboxylic Acid Salt

A series of cross-linked waterborne polyurethane/hexamethoxymethylmel-amine-carbon nanotube nanocomposites (WBPU/HMMM-CNT) were synthesized using carboxylic group functionalized CNT. The carboxylic groups on CNT were reacted with the methoxy groups of HMMM to get bonded HMMM-CNT. Unreacted methoxy group of HMMM-CNT was crosslinked with the carboxylic acid salt groups of WBPU and made crosslinked WBPU/HMMM-CNT nanocomposite. The mechanical properties (tensile strength and Young’s modulus) of conventional WBPU, crosslinked WBPU/HMMM, WBPU/CNT and WBPU/HMMM-CNT nanocomposites were compared under three conditions: untreated, wet and dried. It was observed that the mechanical properties of the crosslinked WBPU/HMMM-CNT nanocomposites were the least affected by water compared to conventional WBPU, crosslinked WBPU/HMMM, and WBPU/CNT nanocomposites. Differential scanning calorimetry (DSC) analysis also confirmed that the WBPU/HMMM-CNT nanocomposite can absorbed least water which can be easily removed by heating without destroying their crystalline structure. Crosslinked WBPU/HMMM-CNT nanocomposite recovered most of its mechanical properties of (with optimum HMMM-CNT content) after drying.

scholarly journals Combined Effects of Cellulose Nanofiber Nucleation and Maleated Polylactic Acid Compatibilization on the Crystallization Kinetic and Mechanical Properties of Polylactic Acid Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3226
Author(s):  
Siti Shazra Shazleen ◽  
Lawrence Yee Foong Ng ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Polylactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Kinetic ◽  
Crystallization Rate ◽  
Combined Effects ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Isothermal Crystallization Kinetics

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.

Hydrodegradation of starch incorporated polylactic acid with acrylic acid as interfacial linker

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Yinghong Xiao ◽  
Jianfei Che ◽  
Anne Bergeret ◽  
Chun Mao ◽  
Jian Shen
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polylactic Acid ◽  
Interfacial Adhesion ◽  
Composite Graft ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Graft Modification ◽  
Scanning Electron

AbstractGraft modification of polylactic acid (PLA) with acrylic acid (AA) using double initiators was studied. The composition of the graft copolymer (PLA-AA) was characterized with Fourier transform infrared (FTIR) spectroscopy and introduction of AA was demonstrated. Differential scanning calorimetry (DSC) analysis indicated that due to the increasing graft efficacy the modified PLA had better interfacial adhesion with starch compared to neat PLA. Fracture surfaces of starch/PLA and starch/PLA-AA were observed using scanning electron microscope (SEM) and the results also demonstrated the better interfacial adhesion of the latter composite. Graft modification of PLA matrix and introduction of starch played important roles in enhancing the mechanical properties (strength and modulus) while remaining good degradability of the composite.

scholarly journals Studying the Effects of Adding Silica Sand Nanoparticles on Epoxy Based Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Tahir Ahmad ◽  
Othman Mamat ◽  
Rafiq Ahmad
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix Composite ◽  
Silica Sand ◽  
Degree Of Crystallinity ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Inorganic Particles ◽  
The Past ◽  
The Subject ◽  
Experimental Values

The research about the preparation of submicron inorganic particles, once conducted in the past decade, is now leading to prepare polymer matrix composite (PMC) reinforced with nanofillers. The objective of present research is to study the modified effects of reinforcement dispersion of nanoparticle silica in epoxy resin on the physical properties, mechanical and thermal behaviour, and the microstructure of resultant composites. Stirrer mixing associated with manual mixing of silica sand nanoparticles (developed in our earlier research) (Ahmad and Mamat, 2012) into epoxy was followed by curing being the adopted technique to develop the subject nanocomposites. Experimental values showed that 15 wt.% addition of silica sand nanoparticles improves Young’s modulus of the composites; however, a reduction in tensile strength was also observed. Number of holes and cavities produced due to improper mixing turn out to be the main cause of effected mechanical properties. Addition of silica sand nanoparticles causes a reduction in degree of crystallinity of the nanocomposites as being observed in differential scanning calorimetry (DSC) analysis.

scholarly journals Research on Polyethylene Glycol, Crosslinked Polyethylene Glycol & Polyethylene Glycol Chitosan Conjugate Coating for Biomedical Application

2019 ◽  
Vol 8 (2S11) ◽  
pp. 2921-2925 ◽  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Glycol ◽  
Bacterial Adhesion ◽  
Biomedical Application ◽  
Antimicrobial Properties ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Glycol Chitosan ◽  
Coating Materials

Polyethylene glycol used as coating materials because it resist to protein adsorption and bacterial adhesion. Polyethylene glycol and crosslinked polyethylene glycol & polyethylene glycol chitosan conjugate used for coating glass implants. Fourier transform infrared spectroscopy (FTIR) analysis showed proper crosslinking in crosslinked polyethylene glycol but in polyethylene glycol & chitosan conjugate no reaction takes place. Scanned Electron Microscope (SEM) used for study of surface morphology. Polyethylene glycol & chitosan conjugate have smoother surface than pure polyethylene glycol, polyethylene glycol chitosan conjugate. Differential scanning calorimetry (DSC) analysis used for glass transition temperature study. Crosslinked polyethylene glycol has good mechanical properties. Antimicrobial properties of polyethylene glycol chitosan conjugate are good in comparison to pure polyethylene glycol, crosslinked polyethylene glycol.

Proximity and conformation effects in 29Si and 13C NMR spectra of di-ortho substituted trimethylsiloxybenzenes

1990 ◽  
Vol 55 (8) ◽  
pp. 2027-2032 ◽  
Author(s):  
Jan Schraml ◽  
Robert Brežný ◽  
Jan Čermák
Keyword(s):  
Benzene Ring ◽  
13C Nmr ◽  
Proximity Effect ◽  
Nmr Spectra ◽  
Methoxy Group ◽  
Chemical Shifts ◽  
Proximity Effects ◽  
13C Nmr Spectra ◽  
Methoxy Groups ◽  
C Nmr

29Si and 13C NMR spectra of five 4-substituted 2,6-dimethoxytrimethylsiloxybenzenes were studied with the aim to elucidate the nature of the deshielding proximity effects observed in the spectra of ortho substituted trimethylsiloxybenzenes. The sensitivity of 29Si chemical shifts to para substitution is in the studied compounds essentially the same as in mono ortho methoxytrimethylsiloxybenzenes. The deshielding proximity effect of the ìsecondî methoxy group is somewhat smaller than that of the ìfirstî group. The present results indicate that the two methoxy groups assume coplanar conformations with the benzene ring and are turned away from the trimethylsiloxy group which is not in the benzene plane. It is argued that in mono ortho methoxytrimethylsiloxybenzenes the two substituent groups adopt the same conformations as in the compounds studied here.

scholarly journals The effect of polyhedral oligomeric silsesquioxanes (POSSs) incorporation in ethylene-propylene-diene-terpolymer (EPDM): a thermal study

2021 ◽  
Author(s):  
Ignazio Blanco ◽  
Traian Zaharescu
Keyword(s):  
Room Temperature ◽  
Thermal Characterization ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Dsc Analysis ◽  
Γ Irradiation ◽  
Scanning Calorimetry ◽  
Ethylene Propylene ◽  
Oligomeric Silsesquioxane ◽  
Ethylene Propylene Diene Terpolymer ◽  
Dynamic Heating

AbstractA series of ethylene-propylene-diene-terpolymer (EPDM)/polyhedral oligomeric silsesquioxane (POSS) composites at different percentage of POSS were prepared and subjected to γ-irradiation. Both irradiated and non-irradiated EPDM and composites were investigated by the means of thermal analysis to verify if the presence of POSS molecules is able to reduce the oxidation level of free radicals generated during the degradation and to evaluate the effects of the irradiation. EPDM composites at 1, 3 and 5 mass% of POSS were thus degraded in a thermogravimetric (TG) balance in dynamic heating conditions (25–700 °C), in both inert and oxidative atmosphere by flowing nitrogen and air respectively. Thermal characterization was then completed by carrying out Differential Scanning Calorimetry (DSC) analysis from sub-ambient to better highlight the melting of the polymer and polymer composites occurring just above the room temperature. FTIR spectroscopy was also performed for the prepared samples to check the presence of the molecular filler in the composites and for the TG’s residue at 700 °C, in order to evaluate its nature. DSC and TGA parameters were detected and discussed to have information about the effect of the degradation’s environment, the effect of irradiation on polymer stabilization and the effect of POSS content in the polymer matrix.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

scholarly journals Effect of Multiple Reflows on the Interfacial Reactions and Mechanical Properties of an Sn-0.5Cu-Al(Si) Solder and a Cu Substrate

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2367
Author(s):  
Junhyuk Son ◽  
Dong-Yurl Yu ◽  
Yun-Chan Kim ◽  
Shin-Il Kim ◽  
Min-Su Kim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Heat ◽  
Interfacial Reactions ◽  
Future Application ◽  
Scanning Calorimetry ◽  
Cross Sectional ◽  
Automotive Electronic ◽  
Transmission Electron ◽  
Si Content ◽  
Lead Free Solders

In this study, the interfacial reactions and mechanical properties of solder joints after multiple reflows were observed to evaluate the applicability of the developed materials for high-temperature soldering for automotive electronic components. The microstructural changes and mechanical properties of Sn-Cu solders regarding Al(Si) addition and the number of reflows were investigated to determine their reliability under high heat and strong vibrations. Using differential scanning calorimetry, the melting points were measured to be approximately 227, 230, and 231 °C for the SC07 solder, SC-0.01Al(Si), and SC-0.03Al(Si), respectively. The cross-sectional analysis results showed that the total intermetallic compounds (IMCs) of the SC-0.03Al(Si) solder grew the least after the as-reflow, as well as after 10 reflows. Electron probe microanalysis and transmission electron microscopy revealed that the Al-Cu and Cu-Al-Sn IMCs were present inside the solders, and their amounts increased with increasing Al(Si) content. In addition, the Cu6Sn5 IMCs inside the solder became more finely distributed with increasing Al(Si) content. The Sn-0.5Cu-0.03Al(Si) solder exhibited the highest shear strength at the beginning and after 10 reflows, and ductile fracturing was observed in all three solders. This study will facilitate the future application of lead-free solders, such as an Sn-Cu-Al(Si) solder, in automotive electrical components.

Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

2021 ◽  
pp. 002199832199945
Author(s):  
Jong H Eun ◽  
Bo K Choi ◽  
Sun M Sung ◽  
Min S Kim ◽  
Joon S Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Internal Damage ◽  
Impact Tests ◽  
Flexural Tests ◽  
The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

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