scholarly journals Novel green biodegradable polylactide based polyurethane triblock copolymers reinforced with cellulose nanowhiskers

2021 ◽  
Author(s):  
Noha Ali Abdel Hady
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Cell Attachment ◽  
Triblock Copolymers ◽  
Cellulose Nanowhiskers ◽  
Angle Measurements ◽  
Degradation Rates ◽  
Contact Angle Measurements ◽  
Enhance Cell Attachment ◽  
Final Composition

Novel green classes of biodegradable polylactide-based triblock polyurethane (TBPU) polymers were synthesized. Owing to their tailored mechanical properties, improved degradation rates, and the enhance cell attachment potential compared with polylactide-homopolymer, they tested for biomedical applications. Triblock copolymers (TB) of different lactide and polyethylene glycol composition were first fabricated by ring-opening polymerization using tin octoate as catalyst. Afterwich polycaprolactone diole (PCL-diole) is reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as nontoxic chain extender to form the final TBPUs. Final composition, molecular weight, thermal properties, hydrophilicity and biodegradation of the obtained TB and TBPU were studied and characterized using 1H-NMR, GPC, FTIR, DSC, SEM and contact angle measurements. Results obtained from the high molecular weight members of TBPUs showed improved hydrophilicity and degradation rates along with tailored mechanical properties. Nanocomposites obtained by reinforcing TBPU3 with 7% (w/w) BCNW showed ~16% increase in tensile strength and 330% in % elongation compared with PL-homopolymer. Those polymers and their nanocomposites demonstrated promising potential to be used as bone cement, and in regenerative medicin.

scholarly journals Novel green biodegradable polylactide based polyurethane triblock copolymers reinforced with cellulose nanowhiskers

2021 ◽  
Author(s):  
Noha Ali Abdel Hady
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Cell Attachment ◽  
Triblock Copolymers ◽  
Cellulose Nanowhiskers ◽  
Angle Measurements ◽  
Degradation Rates ◽  
Contact Angle Measurements ◽  
Enhance Cell Attachment ◽  
Final Composition

Novel green classes of biodegradable polylactide-based triblock polyurethane (TBPU) polymers were synthesized. Owing to their tailored mechanical properties, improved degradation rates, and the enhance cell attachment potential compared with polylactide-homopolymer, they tested for biomedical applications. Triblock copolymers (TB) of different lactide and polyethylene glycol composition were first fabricated by ring-opening polymerization using tin octoate as catalyst. Afterwich polycaprolactone diole (PCL-diole) is reacted with TB copolymers using 1,4-butane diisocyanate (BDI) as nontoxic chain extender to form the final TBPUs. Final composition, molecular weight, thermal properties, hydrophilicity and biodegradation of the obtained TB and TBPU were studied and characterized using 1H-NMR, GPC, FTIR, DSC, SEM and contact angle measurements. Results obtained from the high molecular weight members of TBPUs showed improved hydrophilicity and degradation rates along with tailored mechanical properties. Nanocomposites obtained by reinforcing TBPU3 with 7% (w/w) BCNW showed ~16% increase in tensile strength and 330% in % elongation compared with PL-homopolymer. Those polymers and their nanocomposites demonstrated promising potential to be used as bone cement, and in regenerative medicin.

Surface-modified halloysite nanotubes as fillers applied in reinforcing the performance of polytetrafluoroethylene

Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 643-656 ◽  
Author(s):  
Zhi-Lin Cheng ◽  
Xing-Yu Chang ◽  
Zan Liu ◽  
Dun-Zhong Qin
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Sodium Dodecyl ◽  
Halloysite Nanotubes ◽  
Angle Measurements ◽  
Transmission Electron ◽  
Contact Angle Measurements ◽  
Ftir Spectrometry ◽  
Surface Modified ◽  
Scanning Electron

ABSTRACTIn order to improve the dispersibility of halloysite nanotubes (HNTs) in polytetrafluoroethylene (PTFE), the modification of HNT surfaces was studied with three types of modifiers (polymethyl methacrylate [PMMA], sodium dodecyl sulfate [SDS] and carboxylic acid). The modified HNTs were characterized by Fourier-transform infrared (FTIR) spectrometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and contact angle measurements. The HNTs were used to reinforce the mechanical properties of PTFE. The mechanical results indicated that the tensile strength of the modified HNT-filled PTFE nanocomposites (F-HNT/PTFE) improved to an acceptable degree and Young's modulus increased significantly. The tribological results showed that the wear rate of F-HNT/PTFE decreased by 21–82 and 9–40 times compared to pure PTFE and the pristine F-HNT/PTFE, respectively.

Degradation of Hydrophobic Surface Coatings Under Water Exposure

2018 ◽  
Author(s):  
Matthew A. Trapuzzano ◽  
Rasim Guldiken ◽  
Andrés Tejada-Martínez ◽  
Nathan B. Crane
Keyword(s):  
Contact Angle ◽  
Material Selection ◽  
Contact Angle Hysteresis ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Water Exposure ◽  
Angle Measurements ◽  
Degradation Rates ◽  
Contact Angle Measurements ◽  
Receding Contact

Many important processes depend on the wetting of liquids on surfaces. Wetting is commonly controlled through material selection, coatings, and/or surface texture, however these means are sensitive to environmental conditions. Some “hydrophobic” fluoropolymer coatings are sensitive to extended water exposure as evidenced by declining contact angles and increasing contact angle hysteresis. Understanding degradation of these coatings is critical to processes that employ them. To accomplish this, contact angle measurements were taken before, during, and after slides coated with FluoroSyl 3750 or Cytop were submerged in water, or vibrated while covered in water. Both methods demonstrated similar changes in advancing contact angle though vibration increased degradation rates significantly. However, it does not simply accelerate the process as different trends are apparent in receding contact angles. The FluoroSyl 3750 showed no clear degradation under either condition. Surface profilometry did not detect any surface morphology differences that might cause contact angle change.

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.

Estimating the Mechanical Properties of Retinal Tissue Using Contact Angle Measurements of a Spreading Droplet

Langmuir ◽  
2013 ◽  
Vol 29 (16) ◽  
pp. 5080-5084 ◽  
Author(s):  
Colin A. Grant ◽  
Peter C. Twigg ◽  
Michael D. Savage ◽  
W. Hong Woon ◽  
Mark Wilson ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Retinal Tissue ◽  
Angle Measurements ◽  
Contact Angle Measurements

Utilization of Plasma Treated Polymeric Macro-Fibers as Reinforcement in Concrete Constructions

2017 ◽  
Vol 1144 ◽  
pp. 70-75
Author(s):  
Jan Trejbal ◽  
Josef Fládr ◽  
Lubomír Kopecký
Keyword(s):  
Mechanical Properties ◽  
Plasma Treatment ◽  
Treatment Duration ◽  
Negative Impact ◽  
Fiber Surface ◽  
Cement Matrix ◽  
Bending Tests ◽  
Four Point Bending ◽  
Angle Measurements ◽  
Contact Angle Measurements

Polymeric macro fibers BeneSteel having diameter equal to 480 μm and length 55 mm were treated in low pressure oxygen plasma by different treatment duration from 5 to 480 s to attain the better interaction with cement matrix (focused on both, chemical and physical bond). An effect of realized treatment was examined through fiber surface water wettability observation by direct horizontal optical method enabling contact angle measurements. Next, the pertinent negative impact of plasma treatment on fibers mechanical properties was examined by several methods. It was shown that the most effective plasma treatment duration is up to 30 s. Thus treated fibers exhibited the better wettability by ca. 110 % in comparison with reference fibers, while its mechanical properties were not negatively affected. Finally, reference and 30 s plasma treated fibers were used as randomly dispersed reinforcement in concrete specimens. Mechanical properties of these composites were examined by four-point bending tests. Specimens containing treated fibers exhibited bigger fracture toughness by ca. 30 % beside the reference ones, while the first cracking strength stayed constant in all cases.

scholarly journals Development and Characterization of a Poly (Vinyl Alcohol)/Graphene Oxide Composite Hydrogel as An Artificial Cartilage Material

2018 ◽  
Vol 8 (11) ◽  
pp. 2272 ◽  
Author(s):  
Yibo Zhao ◽  
Wataru Terai ◽  
Yuko Hoshijima ◽  
Kazuma Gotoh ◽  
Koji Matsuura ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Vinyl Alcohol ◽  
Cell Attachment ◽  
Tensile Tests ◽  
Composite Hydrogel ◽  
Poly Vinyl Alcohol ◽  
Sem Images ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Surface Contact Angle

Poly (vinyl alcohol) hydrogel (PVA-H) is expected to be a suitable artificial articular cartilage material because of its high biocompatibility. However, it is difficult to affix to the surface of a living joint because it is bioinert and its mechanical strength needs to be improved. In this study, graphene oxide (GO) subjected to two oxidation rounds was used to form a nanocomposite material and the composite hydrogel PVA-GO-H was prepared by low-temperature crystallization. Scanning electron microscope (SEM) images showed that the addition of GO can increase roughness of the hydrogel surface. Contact angle measurements showed that the surface of PVA-GO-H exhibited hydrophobicity that increased with GO concentration and not with that of PVA-H, indicating that the hydrophilic parts of PVA and GO form hydrogen bonds and the hydrophobic part of GO was exposed on the surface. Tensile tests demonstrated that Young’s modulus was enhanced on the addition of GO. Osteoblast cells showed more affinity for PVA-GO-H than PVA-H, which much more cells adhere to than to PVA-GO-H after a certain period of culturing, suggesting GO can improve the cell attachment of PVA-H. Further studies on the influence of the oxidation time of GO are still required.

scholarly journals Choosing an Effective Compatibilizer for a Virgin HDPE Rich-HDPE/PP Model Blend

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3567
Author(s):  
Erdal Karaagac ◽  
Thomas Koch ◽  
Vasiliki-Maria Archodoulaki
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Polymer Blend ◽  
Random Copolymer ◽  
Shell Morphology ◽  
Mechanical Recycling ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Packaging Industry ◽  
Styrene Butadiene

The most widely used commodity polymers in the rigid packaging industry are polypropylene (PP) and high-density polyethylene (HDPE). For example, blow molding grade of HDPE as a bottle and injection molding grade of PP as a cap are often used to produce detergent bottles. Therefore, the recycled HDPE bottles from post-consumer waste include PP as a contaminant originated from PP bottle caps. To simulate mechanical recycling of bottle waste, the mechanical properties of HDPE-rich-HDPE/PP virgin model blend were studied. For compatibilization, ethylene-based olefin block copolymer, propylene-based olefin block copolymer, ethylene propylene random copolymer, and styrene-butadiene-styrene triblock copolymer were chosen as potential compatibilizer candidates. Contact angle measurements, morphological analysis, adhesion tests of compatibilizer candidates to polymer blend components and the tensile as well as tensile impact properties of the ternary blends were studied. It was found that the ethylene-based olefin block copolymer was the most effective compatibilizer resulting in a return of mechanical properties to those of neat vHDPE due to its ability to encapsulate dispersed vPP particles in a vHDPE matrix (core-shell morphology) and the best adhesion to polymer blend components.

Structure, Wettability and Thermal Degradation of New Fluoro-Oligomer Modified Nanoclays

2008 ◽  
Vol 8 (4) ◽  
pp. 1835-1841 ◽  
Author(s):  
R. Valsecchi ◽  
M. Viganò ◽  
M. Levi ◽  
S. Turri
Keyword(s):  
Molecular Weight ◽  
Exchange Process ◽  
X Rays ◽  
Electronic Microscopy ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Angle Measurements ◽  
Peculiar Behaviour ◽  
Contact Angle Measurements ◽  
Hysteresis Phenomena

Quaternary ammonium salts based on monofunctionalized Perfluoropolyether (PFPE) oligomers were synthesized and used for the cation exchange process of sodium Montmorillonite nanoclays. The new fluoromodified nanoclays were characterized through X-rays diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), termogravimetric analysis (TGA), differential scanning calorimetry (DSC), electronic microscopy (SEM-EDS), and contact angle measurements (CA). In particular XRD showed rather complex patterns (presence of higher order reflections) which allowed the calculation of basal spacings, regularly increasing with the molecular weight of the fluorinated macrocation. Both IR and SEM confirmed the presence of fluorinated segments at clays interface, while TGA showed a limited thermal stability with an onset of degradation temperature which seems not dependent on the molecular weight of the macrocation. CA measurements showed a peculiar behaviour, with evident dynamic hysteresis phenomena and surface tension components quite different from those of commercially available, organomodified clays.

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