scholarly journals Improving the Thermal and Mechanical Properties of Poly(l-lactide) by Forming Nanocomposites with an in Situ Ring-Opening Intermediate of Poly(l-lactide) and Polyhedral Oligomeric Silsesquioxane

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 748 ◽  
Author(s):  
Xiu-Xiu Lei ◽  
Hao Lu ◽  
Lei Lu ◽  
Hai-Qing Xu ◽  
Ying-Guo Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Test ◽  
Ring Opening ◽  
Morphological Characteristics ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Nucleation Effect ◽  
Mass Fractions ◽  
Ring Open

In this study, a series of poly(l-lactide) and (3-amino)-propylheptaisobutyl cage silsesquioxane (PLLA-AMPOSS) intermediates were first fabricated using single-arm in situ solution polymerization of LLA monomers and AMPOSS nanoparticles with different contents, 0.02–1.00 mol%. Then, the PLLA-AMPOSS intermediate with 0.5 mol% AMPOSS was selected as a representative and investigated by nuclear magnetic resonance (NMR) and X-ray diffraction (XRD). Afterwards, it was added into the pure PLLA with different mass fractions. Finally, the thermal behavior, crystallization kinetics, morphological characteristics, and mechanical properties of the obtained PLLA/PLLA-AMPOSS nanocomposites were carefully measured and investigated by differential scanning calorimetry (DSC), polarizing microscopy (POM), scanning electron microscopy (SEM), and tensile test. After comparing the PLLA-AMPOSS intermediate and PLLA/AMPOSS blend, the results show that the ring-open polymerization of PLLA-AMPOSS intermediate was successful. The results also show that the existence of PLLA-AMPOSS has a strong influence on the crystallization behavior of PLLA/PLLA-AMPOSS composites, which can be attributed to the heterogeneous nucleation effect of PLLA-AMPOSS. In addition, it was also found from the tensile test results that the addition of the PLLA-AMPOSS nanofiller improved the tensile strength and strain at break of PLLA/PLLA-AMPOSS nanocomposites. All of these results indicate the good nucleating effect of PLLA-AMPOSS and that the AMPOSS disperses well in the PLLA/PLLA-AMPOSS nanocomposites. A conclusion can be drawn that the selective nucleating agent and the combined method of in situ ring-opening polymerization and physical blending are feasible and effective.

Analysis of the Mechanical Properties of Solvent Cast Blends of PLA/PCL

2014 ◽  
Vol 679 ◽  
pp. 50-56 ◽  
Author(s):  
Yuan Yuan Chen ◽  
Luke M. Geever ◽  
Clement L. Higginbotham ◽  
Declan M. Devine
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Tensile Test ◽  
Ductile Material ◽  
Infrared Spectrometry ◽  
Significant Shift ◽  
Scanning Calorimetry ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Mass Fractions

Polylactic acid (PLA) is the most promising material in the biodegradable category. However, brittleness and poor thermal stability restrict its application. To overcome this limitation, PLA may be blended with other biodegradable materials to tailor its properties while maintain biodegradability. In this study a series of blends of PLA and poly (ε-caprolactone) (PCL) with various mass fractions were prepared by solution method and solvent casting. Films of each blend were formed when the solvent evaporated. Subsequently, tensile test samples were punched out of the film for testing and tensile testing, Fourier transform infrared spectrometry (FTIR), Differential scanning Calorimetry (DSC) and contact angle measurements were carried out. Since PCL is a ductile material, the two materials were blended together in an effort to improve the mechanical properties. However, on thermal analysis of the blends, two individual melting peaks were observed in the DSC thermograms. Furthermore, no significant shift in peaks was observed on the FTIR spectra, and clear droplets and boundaries between two components of the blend can be observed in morphology study, all indicated the immiscibility of PLA and PCL. Tensile test showed poor mechanical properties due to the poor adhesion of the two immiscible components of the blend, and the addition of PCL did not influence the wettability of the surface of the blends as there were no significant differences in contact angle measurements.

scholarly journals Improvement of Transparencies and Mechanical Properties of Poly(cyclohexylene dimethylene cyclohexanedicarboxylate) Parts Using a Compounding Nucleating Agent to Control Crystallization

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 563 ◽  
Author(s):  
Bei Su ◽  
Ying-Guo Zhou
Keyword(s):  
Mechanical Properties ◽  
Crystal Size ◽  
Crystallization Process ◽  
Nucleating Agent ◽  
Scanning Calorimetry ◽  
Widespread Application ◽  
Crystallization Behaviors ◽  
Nucleation Effect ◽  
Quantitative Results ◽  
Control Crystallization

Poly(cyclohexylene dimethylene cyclohexanedicarboxylate) (PCCE) is a kind of copolyester polymer with excellent toughness and outstanding flexibility. However, the opacity caused by crystallization limits the widespread application of PCCE in products that have transparency requirements. The effects of 1,3:2,4-Di-p-methylbenzylidene sorbitol (MDBS) on the crystallization behavior, transparency, and mechanical properties of a PCCE melt were investigated via differential scanning calorimetry (DSC), spectrophotometry, and tensile testing. The results suggest that the transparency and mechanical properties of PCCE drastically improve and that its crystallization behaviors are obviously influenced by the addition of MDBS. PCCE with 0.6 wt% MDBS was then selected as a representative sample, and its thermal behavior and crystal morphology were further investigated by DSC, hot-staged polarizing microscopy (HSPLM), and scanning electron microscopy (SEM). The quantitative results suggest that, compared to neat PCCE resin, PCCE/MDBS has a lower isothermal and nonisothermal crystallization activation energy, which indicates a rapid crystallization process. The results also show that, compared to the pure PCCE melt, the PCCE/MDBS melt experiences a greater increase in the number of crystals and a greater decrease in the crystal size during cooling. The acceleration of the crystallization process and reduction in crystal size can be both attributed to the nucleation effect of the MDBS. In conclusion, because the addition of the nucleating agent improves the transparency and tensile properties of PCCE by adjusting and controlling its thermal and crystallization behaviors, the proposed technique of using a compounding nucleating agent to control crystallization is therefore suitable for PCCE.

In Situ Synthesis of Nylon 6/MgAl Layered Double Hydroxide (LDH) Nanocomposites by Hydrolyzed Ring Opening Polymerization

2013 ◽  
Vol 671-674 ◽  
pp. 1883-1888 ◽  
Author(s):  
Hong Lin Li ◽  
Gui Sheng Yang ◽  
Yu Cheng Wu
Keyword(s):  
Ring Opening ◽  
Nylon 6 ◽  
Ring Opening Polymerization ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nucleation Effect ◽  
Transmission Electron ◽  
Structures And Properties ◽  
Double Hydroxide

Nylon 6/MgAl-LDH nanocomposites had been successfully prepared by In situ hydrolyzed ring opening polymerization in this work. The structures and properties of Nylon 6/MgAl-LDH nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The nanodispersion of exfoliated MgAl-LDH layers in nylon 6 matrix has been verified by the observation of TEM image in Nylon 6/MgAl-LDH nanocomposites with 0.3 wt% MgAl-LDH (MANM-0.3). The XRD results showed that the exfoliated MgAl-LDH favored the formation of the γ-crystalline of nylon 6 form. DSC data showed that the exfoliated MgAl-LDH layers play the role of nucleating agents with strong heterogeneous nucleation effect on the crystallization of nylon 6. But TAG results showed the thermal stability of nylon 6/MgAl-LDH nanocomposites were worse than that of neat nylon 6.

Synthesis and Characterizations of Poly(Butylene Succinate) Copolyester

2014 ◽  
Vol 1015 ◽  
pp. 381-384
Author(s):  
Li Liu ◽  
Li Hai Cai ◽  
Dan Liu ◽  
Jun Xu ◽  
Bao Hua Guo
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Crystallization Temperature ◽  
In Situ Polymerization ◽  
Nucleating Agent ◽  
Single Fiber ◽  
Butylene Succinate ◽  
Crystallization Behaviors ◽  
Polymerization Method

The poly (butylene succinate) (PBS) and 3 wt% attapulgite (ATP) reinforced PBS/ATP nanocomposites with 1,6-hexanediol were fabricated using an in situ polymerization method. The crystallization behaviors indicated that ATP had effectively acted as nucleating agent, resulting in the enhancement on the crystallization temperature. The SEM results showed a superior interfacial linkage between ATP and PBS. Also, ATP could disperse as a single fiber and embed in the polymer matrix, which resulted in the improved mechanical properties.

scholarly journals Microstructure and mechanical properties of slowly cooled Cu47.5Zr47.5Al5

2007 ◽  
Vol 22 (2) ◽  
pp. 326-333 ◽  
Author(s):  
J. Das ◽  
S. Pauly ◽  
C. Duhamel ◽  
B.C. Wei ◽  
J. Eckert
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Volume Fraction ◽  
Spherical Shape ◽  
High Yield ◽  
High Yield Strength ◽  
Scanning Calorimetry ◽  
Arc Melting ◽  
Martensite Matrix

Cu47.5Zr47.5Al5 was prepared by arc melting and solidified in situ by suction casting into 2–5-mm-diameter rods under various cooling rates (200–2000 K/s). The microstructure was investigated along the length of the rods by electron microscopy, differential scanning calorimetry and mechanical properties were investigated under compression. The microstructure of differently prepared specimens consists of macroscopic spherical shape chemically inhomogeneous regions together with a low volume fraction of randomly distributed CuZr B2 phase embedded in a 2–7 nm size clustered “glassy-martensite” matrix. The as-cast specimens show high yield strength (1721 MPa), pronounced work-hardening behavior up to 2116 MPa and large fracture strain up to 12.1–15.1%. The fracture strain decreases with increasing casting diameter. The presence of chemical inhomogenities and nanoscale “glassy-martensite” features are beneficial for improving the inherent ductility of the metallic glass.

scholarly journals A method for pet mechanical properties enhancement

2019 ◽  
Vol 10 (8) ◽  
pp. 1725
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Virgil Petrescu ◽  
Antonio Apicella ◽  
Florian Ion Tiberiu Petrescu
Keyword(s):  
Mechanical Properties ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Molecular Structures ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Shear Transfer ◽  
Crystalline Polymers ◽  
Reactive Compatibilizer

A method for PET mechanical properties enhancement by reactive blending with HBA/HNA Liquid Crystalline Polymers for in situ highly fibrillar composites preparation is presented. LCP/PET blends were reactively extruded in presence of Pyromellitic Di-Anhydride (PMDA) and then characterized by Differential Scanning Calorimetry, Thermally Stimulated Currents and tensile mechanical properties. Moderate amounts of LCP in the PET (0.5 and 5%) and small amounts of thermo-active and reactive compatibilizer in the blend (0.3%) were found to significantly improve LCP melt dispersion, melts shear transfer and LCP fibril formation and adhesion. An unexpected improvement was probably due to the presence of two distinct phases’ supra-molecular structures involving PET-LCP and PMDA.

Crystallization Behavior of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2012 ◽  
Vol 184-185 ◽  
pp. 932-935
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
Crystallization Process ◽  
In Situ Polymerization ◽  
Nucleating Agent ◽  
Lower Content ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Montmorillonite Nanocomposites

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The crystallization behavior of PE/MMT nanocomposites at different MMT concentrations (from 0.1 to 1.2 wt %) were investigated by differential scanning calorimetry (DSC). The equilibrium melting points increase by the addition of MMT. The crystallization rates of PE/MMT nanocomposites are faster than those of pure PE. The addition of MMT facilitated the crystallization of PE, with the MMT functioning as a heterogeneous nucleating agent at lower content; at higher concentrations, however, the physical hindrance of the MMT layers to the motion of PE chains retarded the crystallization process.

scholarly journals Fabrication, Crystalline Behavior, Mechanical Property and In-Vivo Degradation of Poly(l–lactide) (PLLA)–Magnesium Oxide Whiskers (MgO) Nano Composites Prepared by In-Situ Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1123 ◽  
Author(s):  
Hui Liang ◽  
Yun Zhao ◽  
Jinjun Yang ◽  
Xiao Li ◽  
Xiaoxian Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Oxide ◽  
Bone Repair ◽  
In Situ Polymerization ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Biomedical Material ◽  
In Vivo Degradation

The present work focuses on the preparation of poly(l–lactide)–magnesium oxide whiskers (PLLA–MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA–MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA–MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA–MgO composite to serve as a biomedical material for bone-related repair.

scholarly journals A comparison of mechanical properties and X-ray tomography analysis of different out-of-autoclave manufactured thermoplastic composites

2020 ◽  
Vol 39 (19-20) ◽  
pp. 703-720
Author(s):  
Diego Saenz-Castillo ◽  
María I Martín ◽  
Vanessa García-Martínez ◽  
Abhiram Ramesh ◽  
Mark Battley ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Raw Material ◽  
Thermoplastic Composites ◽  
Scanning Calorimetry ◽  
Consolidation Process ◽  
Plane Shear ◽  
X Ray ◽  
Void Distribution ◽  
Out Of Autoclave

Three different out-of-autoclave manufacturing processes of CF/poly-ether-ether-ketone thermoplastic composites were characterized, including innovative laser-assisted automated fibre placement with in situ consolidation. Characterization techniques included differential scanning calorimetry, ultrasonic non-destructive testing and matrix digestion, in addition to 3D X-ray microcomputed tomography to investigate the void distribution, size and shape. The results revealed that in situ consolidation process can lead to the accumulation of large voids between the upper layers. Interlaminar shear, in-plane shear, tensile and flexure testing were used for mechanical evaluation. A reduction in the mechanical properties was observed for in situ consolidation laminates when compared to the other out-of-autoclave methods. The drop in mechanical properties of in situ consolidation laminates was mainly attributed to the differences found in void distribution and size. Optimization of processing parameters along with higher quality prepreg raw material could be of assistance for the improvement of mechanical properties of in situ consolidation structures.

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