Biodegradable Nanocomposites of Poly(hydroxybutyrate-co-hydroxyvalerate): The Effect of Nanoparticles

2008 ◽  
Vol 8 (4) ◽  
pp. 1858-1866 ◽  
Author(s):  
Pralay Maiti ◽  
Jaya P. Prakash Yadav
Keyword(s):  
Mechanical Properties ◽  
Layered Silicate ◽  
Layered Silicates ◽  
Thermal And Mechanical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silicate Nanocomposites ◽  
Transmission Electron ◽  
Superior Mechanical Properties ◽  
Biodegradable Nanocomposites

Copolymer of hydroxybutyrate and hydroxyvalerate, P(HB-HV)/layered silicate or hydroxyapatite nanocomposites were prepared via melt extrusion. The nanostructure, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated hybrids for layered silicates. Hydroxyapatite of nanometer dimension is uniformly distributed in matrix copolymer. The nanohybrids show significant improvement in thermal and mechanical properties of the copolymer as compared to the neat copolymer. The layered silicate nanocomposites exhibit superior mechanical properties as compared to hydroxyapatite nanohybrid. The thermal expansion coefficient is significantly reduced in nanohybrids. The biodegradability of pure copolymer and its nanocomposites were studied at room temperatures under controlled conditions in compost media. The rate of biodegradation of copolymer is enhanced dramatically in the nanohybrids. Hydroxyapatite hybrid shows highest rate of biodegradation. The change in biodegradation is streamlined in terms of nature of nanoparticles used to prepare hybrids.

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

Biodegradable Polyester / Layered Silicate Nanocomposites

2002 ◽  
Vol 740 ◽  
Author(s):  
Pralay Maiti ◽  
Carl A. Batt ◽  
Emmanuel P. Giannelis
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Layered Silicate ◽  
Layered Silicates ◽  
Melt Extrusion ◽  
Biodegradable Polyester ◽  
Modified Montmorillonite ◽  
Organically Modified Montmorillonite ◽  
Silicate Nanocomposites ◽  
Organically Modified

ABSTRACTNanocomposites of α-hydroxy polyester, polylactide (PLA) and β-hydroxy polyester, polyhydroxybutyrate (PHB) with layered silicates have been successfully prepared by melt extrusion of PLA and PHB with organically modified montmorillonite (MMT) and fluoromica. The mechanical properties of the nanocomposites are improved compared to the neat polymers. Storage modulus increase up to 40% compared with the pure polymers by adding only 2–3 wt% nanoclay. Biodegradation can be controlled by the choice of the nanoclay used.

scholarly journals Synthesis, Physical Properties and Enzymatic Degradation of Biodegradable Nanocomposites Fabricated Using Poly(Butylene Carbonate-Co-Terephthalate) and Organically Modified Layered Zinc Phenylphosphonate

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2149
Author(s):  
Li-Ying Tseng ◽  
Erh-Chiang Chen ◽  
Jie-Mao Wang ◽  
Tzong-Ming Wu
Keyword(s):  
Nmr Spectra ◽  
Enzymatic Degradation ◽  
Molar Ratio ◽  
Wide Angle ◽  
Mixing Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Organically Modified ◽  
Biodegradable Nanocomposites

A new biodegradable aliphatic-aromatic poly (butylene carbonate-co-terephthalate) (PBCT-85) with the molar ratio [BC]/[BT] = 85/15, successfully synthesized through transesterification and polycondensation processes, was identified using 1H-NMR spectra. Various weight ratios of PBCT/organically modified layered zinc phenylphosphonate (m-PPZn) nanocomposites were manufactured using the solution mixing process. Wide-angle X-ray diffraction and transmission electron microscopy were used to examine the morphology of PBCT-85/m-PPZn nanocomposites. Both results exhibited that the stacking layers of m-PPZn were intercalated into the PBCT-85 polymer matrix. The additional m-PPZn into PBCT-85 copolymer matrix significantly enhanced the storage modulus at −70 °C, as compared to that of neat PBCT-85. The lipase from Pseudomonas sp. was used to investigate the enzymatic degradation of PBCT-85/m-PPZn nanocomposites. The weight loss decreased as the loading of m-PPZn increased, indicating that the existence of m-PPZn inhibits the degradation of the PBCT-85 copolymers. This result might be attributed to the higher degree of contact angle for PBCT-85/m-PPZn nanocomposites. The PBCT-85/m-PPZn composites approved by MTT assay are appropriate for cell growth and might have potential in the application of biomedical materials.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HYPEREUTECTIC Al-Si/AlNp COMPOSITE

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1377-1382 ◽  
Author(s):  
SEULKI PARK ◽  
JINMYUNG CHOI ◽  
BONGGYU PARK ◽  
IKMIN PARK ◽  
YONGHO PARK ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometer ◽  
Microstructural Characterization ◽  
Weight Fraction ◽  
Reinforcement Particle ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superior Mechanical Properties ◽  
Phase Evaluation

Hypereutectic Al - Si alloys with fine and evenly distributed Si precipitates have superior mechanical properties In this study, hypereutectic Al - Si alloy powders which contained 15 and 20wt% Si were prepared by a gas atomization process. 1, 3 and 5wt% AlN particles were blended with the Al - Si alloy powders using turbular mixer. The mixture was consolidated by Hot Press at 550°C for 1h under 60MPa. Relative density of the sintered samples was about 98% of theoretical density. This study was investigated by two ways. One is the effect of reinforcement weight fraction and the other is the effect of Silicon contents on the mechanical properties of the composite. Microstructural characterization and phase evaluation were carried out using X-ray Diffraction, Scanning Electron Microscopy equipped with Energy Dispersive Spectrometer. The results showed that the smaller the reinforcement particle size was and the better its distribution was, the higher ultimate tensile strength and hardness were.

Preparation of Anion Modified Montmorillonite-Polystyrene Nanocomposite by Suspension Polymerization

2009 ◽  
Vol 87-88 ◽  
pp. 499-503
Author(s):  
Yi Wang ◽  
Hui Xia Feng ◽  
Jian Hui Qiu
Keyword(s):  
Thermal Stability ◽  
Anionic Surfactants ◽  
Suspension Polymerization ◽  
Layered Silicate ◽  
High Thermal Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Silicate Nanocomposites ◽  
Ft Ir

To ensure good compatibility between polymer and montmorillonite (MMT), three types organophilic-MMT were prepared and the influence of modifying agent style on the modification effect was studied. The results of X-ray diffraction(XRD) show that the modified reagents are all intercalated into the galleries of MMT, which are also proved by patterns of FT-IR and thermogravimetric analysis(TGA), and the spacing of MMT layers increases from 1.23 nm of the pristine MMT to 2.10nm, 3.52nm and 4.14nm for CTAB, SDS and DBS modified MMT respectively. The results also indicate that the d-spacing and exfoliation degree of anionic surfactants inserted MMT is bigger than that of the cationic surfactants treated MMT, which are usually used to preparation polymer layered silicate nanocomposites in literatures. So PS/SDS-MMT and PS/DBS-MMT nanocomposites were prepared by suspension polymerization. The structure of complex were characterized by XRD and no peak can be observed by the spectra, which suggest that the clay platelets have been exfoliated and dispersed in the PS matrix and the both complex are all have exfoliated structure. FT-IR spectrums analysis confirmed the existence of MMT which implied that the layers of silicate was distributing in composites. The results of TGA show that nanocomposites possess exceptionally high thermal stability and the DBS treated composite has higher thermal stability than that of SDS treated.

The Preparation and Characterization of a Novolac Cured Epoxy-Clay Nanocomposites

2006 ◽  
Vol 939 ◽  
Author(s):  
Tsung-Yen Tsai ◽  
Shau-Tai Lu ◽  
Chih-Hung Li ◽  
Chin-Jei Huang ◽  
Li-Chun Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Benzalkonium Chloride ◽  
Barrier Properties ◽  
Layered Silicates ◽  
Clay Nanocomposites ◽  
Crosslinking Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

ABSTRACTIntercalated or exfoliated nanocomposites were composed by the novolac cured epoxy and one of three different kinds of layered silicates, such as montmorillonite (PK-802), saponite (Semecton-SA) and nontronite (PK-805). The bi-functional modifiers (PI/BEN or MI/BEN) with different ratio, which contained one of the promoters (2-phenylimidazole, PI and 2-methylimidazole, MI) of epoxy and benzalkonium chloride (BEN), were intercalated into the gallery regions of pure clays at the same time and followed by a crosslinking reaction. The properties of novolac cured epoxy/clay nanocomposites were characterized by wild-angle X-ray diffraction (WAXRD), thermal analysis (TGA/DSC), coefficiency of thermal expansion (TMA), mechanical properties (DMA), and transmission electron microscopy (TEM). According to the measurement, these novolac cured epoxy-clay nanocomposites have shown the significant improvement in the thermal, mechanical and barrier properties.

Preparation of Exfoliated Polyethylene/Clay Nanocomposites at High Clay Content

2010 ◽  
Vol 150-151 ◽  
pp. 561-564
Author(s):  
Hao Qun Hong ◽  
Hai Yan Zhang ◽  
Hui He ◽  
De Min Jia
Keyword(s):  
Solid Phase ◽  
Clay Content ◽  
Layered Silicates ◽  
Clay Nanocomposites ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
High Polarity

The polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by melt blending the organic MMT with the ternary-monomer graft copolymers of polyethylene (GPE) which were prepared by solid phase grafting maleic anhydride, methyl methacrylate and butyl acrylate onto PE. Fourier transform infrared spectroscopy was used to characterize the structure of GPE. X-ray diffraction patterns and transmission electron microscopy were used to characterize the morphology of GPE/MMT nanocomposites. Results showed that GPE was an outstanding polymeric material to prepare an exfoliated polymer/layered silicates nanocomposites due to the high polarity of GPE and high graft degree. Most layered silicates still maintain the exfoliated and well dispersed state even at 40 phr OMMT content. The exfoliation of layered silicates was attributed to the well intercalation and easy wetting of the grafted oligomers.

scholarly journals Influence of the Double Bond LDH Clay on the Exfoliation / Intercalation Mechanism of Polyacrylamide Nanocomposite Hydrogels

2018 ◽  
Vol 55 (3) ◽  
pp. 263-268
Author(s):  
Ionut Cristian Radu ◽  
Eugeniu Vasile ◽  
Celina Maria Damian ◽  
Horia Iovu ◽  
Paul Octavian Stanescu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Biomedical Applications ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nanocomposite Hydrogels ◽  
Transmission Electron ◽  
Double Hydroxides ◽  
Classical Cross ◽  
Chemical Cross Linking

The paper focuses on the obtaining of novel nanocomposite hydrogels based on polyacrylamide and layered double hydroxides (LDHs) modified with double bonds. The modification of LDH clay was investigated by FTIR, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analyses. Mechanical properties of the nanocomposite hydrogels were employed by compression and rheological measurements. The formation of exfoliated and intercalated structures was evidenced in transmission electron microscopy (TEM). Chemical cross-linking of hydrogels using both classical cross-linker and modified clay was an efficient method to improve the mechanical properties of novel nanocomposite hydrogels. These hydrogels with improved mechanical properties could be further tested for biomedical applications such as tissue engineering.

scholarly journals Effects of TiO2/SiO2 Reinforced Nanoparticles on the Mechanical Properties of Green Hybrid Coating

2015 ◽  
Vol 47 ◽  
pp. 56-66 ◽  
Author(s):  
Mohammed Gobara
Keyword(s):  
Mechanical Properties ◽  
Sol Gel ◽  
Hardness Test ◽  
Silica Sol ◽  
X Ray Diffraction ◽  
Properties Of Coatings ◽  
X Ray ◽  
Hybrid Silica ◽  
Transmission Electron ◽  
Adhesion Performance

Titanium and silica oxides nanoparticles were introduced into hybrid silica sol–gel/epoxy coating to enhance the mechanical properties of coatings. Titanium dioxide (TiO2) and silica oxide (SiO2) were chemically synthesised before adding to the prepared silica sol gel coating. X-ray diffraction (XRD), Energy-dispersive x-ray analysis (EDX) and Transmission Electron microscope (TEM) were used to characterize the prepared nanoparticles. The coating was then applied to 3003 aluminium alloy (AA3003) surface. The adhesion performance of different sol gel coating compositions was investigated using shear test to define the influence of nanoparticles on adhesive strength of the coating. The Rockwell C hardness test was used to study the micro-hardness of different compositions of sol gel coating. Also, contact angel was used to investigate the hydrophobicity of the coatings. The results showed that there was a significant improvement of the adhesion performance of hybrid silica sol gel coating due to addition of TiO2 and the hydrophobicity of sol gel coating was increased due to addition of SiO2 nanoparticles.

Fullerene-Metal Composites: Phase Transformations During Milling and Sintering

2011 ◽  
Vol 172-174 ◽  
pp. 727-732 ◽  
Author(s):  
Ileana Irais Santana ◽  
Francisco Carlos Robles Hernandez ◽  
Vicente Garibay-Febles ◽  
Hector A. Calderon
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Phase Transformations ◽  
Mechanical Milling ◽  
X Ray Diffraction ◽  
Metal Composites ◽  
X Ray ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma

Composites of Fe-C60and Al C60produced by mechanical milling and sinterized by Spark Plasma Sintering are investigated with special attention to the mechanical properties of the products. The processing involves phase transformations of the fullerenes that are interesting to follow and characterize. This involves formation of tetragonal/rhombohedral diamond and carbides during sintering and milling. Transmission Electron Microscopy (TEM) and Raman Spectroscopy techniques are also used to confirm preliminary results of X Ray Diffraction (XRD) related to the formation of nanostructures i.e., grain size of the crystals during mechanical milling and after sintering, spatial distribution of phases and the different phases that are developed during processing.

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