scholarly journals Vegetable Oil Derived Solvent, and Catalyst Free “Click Chemistry” Thermoplastic Polytriazoles

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Michael C. Floros ◽  
Alcides Lopes Leão ◽  
Suresh S. Narine
Keyword(s):  
Click Chemistry ◽  
Vegetable Oil ◽  
Large Range ◽  
Mechanical And Thermal Properties ◽  
Residual Solvent ◽  
Elongation At Break ◽  
Pharmaceutical Industries ◽  
Synthetic Routes ◽  
Chain Lengths ◽  
Ester Chain

Azide-alkyne Huisgen “click” chemistry provides new synthetic routes for making thermoplastic polytriazole polymers—without solvent or catalyst. This method was used to polymerize three diester dialkyne monomers with a lipid derived 18 carbon diazide to produce a series of polymers (labelled C18C18, C18C9, and C18C4 based on monomer chain lengths) free of residual solvent and catalyst. Three diester dialkyne monomers were synthesized with ester chain lengths of 4, 9, and 18 carbons from renewable sources. Significant differences in thermal and mechanical properties were observed between C18C9 and the two other polymers. C18C9 presented a lower melting temperature, higher elongation at break, and reduced Young’s modulus compared to C18C4 and C18C18. This was due to the “odd-even” effect induced by the number of carbon atoms in the monomers which resulted in orientation of the ester linkages of C18C9 in the same direction, thereby reducing hydrogen bonding. The thermoplastic polytriazoles presented are novel polymers derived from vegetable oil with favourable mechanical and thermal properties suitable for a large range of applications where no residual solvent or catalyst can be tolerated. Their added potential biocompatibility and biodegradability make them ideal for applications in the medical and pharmaceutical industries.

1,4-Diazepines: A Review on Synthesis, Reactions and Biological Significance

2019 ◽  
Vol 16 (5) ◽  
pp. 709-729 ◽  
Author(s):  
Muhammad A. Rashid ◽  
Aisha Ashraf ◽  
Sahibzada S. Rehman ◽  
Shaukat A. Shahid ◽  
Adeel Mahmood ◽  
...  
Keyword(s):  
Biological Activities ◽  
Biological Significance ◽  
Biological Evaluation ◽  
Wide Range ◽  
Pharmaceutical Industries ◽  
Biological Aspects ◽  
Synthetic Routes ◽  
Biological Attributes ◽  
Synthesis Reactions ◽  
Potential Use

Background:1,4-Diazepines are two nitrogen containing seven membered heterocyclic compounds and associated with a wide range of biological activities. Due to its medicinal importance, scientists are actively involved in the synthesis, reactions and biological evaluation of 1,4-diazepines since number of decades.Objective:The primary purpose of this review is to discuss the synthetic schemes and reactivity of 1,4- diazepines. This article also describes biological aspects of 1,4-diazepine derivatives, that can be usefully exploited for the pharmaceutical sector.Conclusion:This review summarizes the abundant literature on synthetic routes, chemical reactions and biological attributes of 1,4-diazepine derivatives. We concluded that 1,4-diazepines have significant importance due to their biological activities like antipsychotic, anxiolytic, anthelmintic, anticonvulsant, antibacterial, antifungal and anticancer. 1,4-diazepine derivatives with significant biological activities could be explored for potential use in the pharmaceutical industries.

scholarly journals Improving Mechanical Properties of PLA/Starch Blends Using Masterbatch Containing Vegetable Oil Based Active Ingredients

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2981
Author(s):  
Bianka Nagy ◽  
Norbert Miskolczi ◽  
Zoltán Eller
Keyword(s):  
Impact Strength ◽  
Vegetable Oil ◽  
Rapeseed Oil ◽  
Flexural Modulus ◽  
Charpy Impact ◽  
Sem Images ◽  
Elongation At Break ◽  
Starch Concentration ◽  
Starch Blends ◽  
Charpy Impact Strength

The aim of this research was to increase the compatibility between PLA and starch with vegetable oil-based additives. Based on tensile results, it can be stated, that Charpy impact strength could be improved for 70/30 and 60/40 blends in both unconditioned and conditioned cases, regardless of vegetable oil, while no advantageous change in impact strength was obtained with PLA-g-MA. Considering sample with the highest starch concentration (50%), the flexural modulus was improved by using sunflower oil-based additive, Charpy impact strength and elongation at break was increased using rapeseed oil-based additive in both conditioned and unconditioned cases. SEM images confirmed the improvement of compatibility between components.

scholarly journals Preparation of Tri(alkenyl)functional Open-Cage Silsesquioxanes as Specific Polymer Modifiers

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1063
Author(s):  
Katarzyna Mituła ◽  
Michał Dutkiewicz ◽  
Julia Duszczak ◽  
Monika Rzonsowska ◽  
Beata Dudziec
Keyword(s):  
Condensation Reaction ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Double Decker ◽  
Application Potential ◽  
Synthetic Routes ◽  
High Yields ◽  
Chain Lengths ◽  
Tga And Dsc ◽  
Melting And Crystallization Temperatures

The scientific reports on polyhedral oligomeric silsesquioxanes are mostly focused on the formation of completely condensed T8 cubic type structures and recently so-called double-decker derivatives. Herein, we report on efficient synthetic routes leading to trifunctionalized, open-cage silsesquioxanes with alkenyl groups of varying chain lengths from -vinyl to -dec-9-enyl and two types of inert groups (iBu, Ph) at the silsesquioxane core. The presented methodology was focused on hydrolytic condensation reaction and it enabled obtaining titled compounds with high yields and purity. A parallel synthetic methodology that was based on the hydrosilylation reaction was also studied. Additionally, a thorough characterization of the obtained compounds was performed, also in terms of their thermal stability, melting and crystallization temperatures (TGA and DSC) in order to show the changes in the abovementioned parameters dependent on the type of reactive as well as inert groups at Si-O-Si core. The presence of unsaturated alkenyl groups has a profound impact on the application potential of these systems, i.e., as modifiers or comonomers for copolymerization reaction.

scholarly journals Grafting Hyperbranched Polymers onto TiO2 Nanoparticles via Thiol-yne Click Chemistry and Its Effect on the Mechanical, Thermal and Surface Properties of Polyurethane Coating

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2817 ◽  
Author(s):  
Feng Zhan ◽  
Lei Xiong ◽  
Fang Liu ◽  
Chenying Li
Keyword(s):  
Click Chemistry ◽  
Tio2 Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Hyperbranched Polymers ◽  
Nanocomposite Coatings ◽  
Mechanical And Thermal Properties ◽  
Nanoparticle Dispersion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Modified

In this study, we proposed a novel and facile method to modify the surface of TiO2 nanoparticles and investigated the influence of the surface-modified TiO2 nanoparticles as an additive in a polyurethane (PU) coating. The hyperbranched polymers (HBP) were grafted on the surface of TiO2 nanoparticles via the thiol-yne click chemistry to reduce the aggregation of nanoparticles and increase the interaction between TiO2 and polymer matrices. The grafting of HBP on the TiO2 nanoparticles surface was investigated by means of X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR) and thermogravimetry analysis (TGA). The thermal and mechanical properties of nanocomposite coatings containing various amounts of TiO2 nanoparticles were measured by dynamic mechanical thermal (DMTA) and tensile strength measurement. Moreover, the surface structure and properties of the newly prepared nanocomposite coatings were examined. The experimental results demonstrate that the incorporation of the surface-modified TiO2 nanoparticles can improve the mechanical and thermal properties of nanocomposite coatings. The results also reveal that the surface modification of TiO2 with the HBP chains improves the nanoparticle dispersion, and the coating surface shows a lotus leaf-like microstructure. Thus, the functional nanocomposite coatings exhibit superhydrophobic properties, good photocatalytic depollution performance, and high stripping resistance.

Preparation of degradable vegetable oil-based waterborne polyurethane with tunable mechanical and thermal properties

2020 ◽  
Vol 139 ◽  
pp. 109994 ◽  
Author(s):  
Zhuding Dai ◽  
Pingping Jiang ◽  
Wenxue Lou ◽  
Pingbo Zhang ◽  
Yanmin Bao ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Vegetable Oil ◽  
Waterborne Polyurethane ◽  
Mechanical And Thermal Properties

scholarly journals Micro and nanocomposites of polybutadienebased polyurethane liners with mineral fillers and nanoclay: thermal and mechanical properties

2017 ◽  
Vol 15 (1) ◽  
pp. 46-52 ◽  
Author(s):  
Pablo Ross ◽  
Germán Escobar ◽  
Guillermo Sevilla ◽  
Javier Quagliano
Keyword(s):  
Thermal Properties ◽  
Polymer Chains ◽  
Toluene Diisocyanate ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mineral Fillers

AbstractMicro and nanocomposites of hydroxyl terminated polybutadiene (HTPB)-based polyurethanes (NPU) were obtained using five mineral fillers and Cloisite 20A nanoclay, respectively. Samples were prepared by the reaction of HTPB polyol and toluene diisocyanate (TDI), and the chain was further extended with glyceryl monoricinoleate to produce the final elastomeric polyurethanes. Mechanical and thermal properties were studied, showing that mineral fillers (20%w/w) significantly increased tensile strength, in particular nanoclay (at 5% w/w). When nanoclay-polymer dispersion was modified with a silane and hydantoin-bond promoter, elongation at break was significantly increased with respect to NPU with C20A. Thermal properties measured by differential scanning calorimetry (DSC) were not significantly affected in any case. The molecular structure of prepared micro and nanocomposites was confirmed by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. Interaction of fillers with polymer chains is discussed, considering the role of silanes in compatibilization of hydrophilic mineral fillers and hydrophobic polymer. The functionalization of nanoclay with HMDS silane was confirmed using FTIR. Microstructure of NPU with C20A nanoclay was confirmed by Atomic Force Microscopy (AFM).

Effect of aspect ratio, surface modification and compatibilizer on the mechanical and thermal properties of ldpe-mwcnt nanocomposites

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarfraz H. Abbasi ◽  
Abdulhadi A. Al-Juhani ◽  
Anwar Ul-Hamid ◽  
Ibnelwaleed A. Hussein
Keyword(s):  
Thermal Properties ◽  
Aspect Ratio ◽  
Yield Strength ◽  
Chemical Modification ◽  
Ultimate Strength ◽  
Multiwall Carbon Nanotubes ◽  
Mechanical And Thermal Properties ◽  
Sem Images ◽  
Elongation At Break ◽  
Ldpe Composites

AbstractIn this work, nanocomposites of low density polyethylene (LDPE) / multiwall carbon nanotubes (MWCNTs) were prepared using melt blending. The effects of CNT aspect ratio, CNT loading, CNT chemical modification and the presence of a compatibilizer (maleated polyethylene) on morphology, mechanical and thermal properties of the CNT/LDPE composites were studied. Different MWCNTs were used: long CNT (LCNT); COOH modified CNT (MCNT) and short CNT (SCNT). FE-SEM images of produced nanocomposites show agglomeration of the MWCNTs. Addition of compatibilizer to both LCNT and MCNT nanocomposites improved their dispersion in the LDPE matrix. Yield strength and modulus increased with loading of various MWCNTs. However, ultimate strength, percent elongation and toughness reduced significantly for CNT loadings of 2% CNT and higher. The addition of maleated PE resulted in improvements of Young’s modulus, yield strength and ultimate strength but no impact on elongation at break or toughness. Addition of compatibilizer did not affect the crystallinity of the produced nanocomposites. In general, the use of CNT with high aspect ratio and the addition of compatibilizer and chemical modification improved the dispersion of MWCNTs and consequently improved most of the mechanical properties except elongation at break and toughness.

Effect of chain extender on the mechanical and thermal resistance properties of polyurethane liners for composite propellants

Polyurethanes ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
P. Ross ◽  
G. Sevilla ◽  
J. Quagliano
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Chain Extender ◽  
Molecular Structures ◽  
Polymer Chains ◽  
Mechanical And Thermal Properties ◽  
Thermal Changes ◽  
Ft Ir ◽  
Chain Lengths

AbstractPolyurethane formulations utilized as liners for composite propellants were prepared by the reaction of toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI) with hydroxyl terminated polybutadiene (HTPB), while polymer chains were further extended with neopentyl glycol diol, NPG triol and two different triols (monoglyceryl ricinoleate, MRG and trimethylolpropane, TMP). Liners were formulated with micronized titanium dioxide mechanically dispersed in hydroxyl-terminated polybutadiene (HTPB). The molecular structures of liners were confirmed by FT-IR. Thermal properties indicated that the nature of chain extender (crosslinker) only slightly affected the temperatures for decomposition of liners. Two main thermal changes were found at 370∘C and another at around 440–500∘C, depending on the chain extender utilized. On the other side, mechanical properties varied within the range of 0,7-1,8 MPa, consistent with this kind of elastomers. Tensile strength at break was only significantly affected with TMP and MRG-chain extended liners at the lowest concentrations tested of 1,3 and 2% (w/w), respectively. However, the behaviour depended on whether TDI or IPDI isocyanate was utilized for curing. TMP 1,3% crosslinked liner cured with TDI had a tensile strength of 1,82MPa whileMRG-crosslinked liner cured with IPDI had a tensile strength of 1,56 MPa. It was observed that at the higher NCO/OH ratios essayed, tensile strength and hardness increased, improving mechanical properties. Our results confirmed that TMP and MRG triols together with NPG diols can be used to tailor mechanical and thermal properties of liners, considering their different hydroxyl functionalities and chain lengths.

scholarly journals Inhalation vs. aspiration of single-walled carbon nanotubes in C57BL/6 mice: inflammation, fibrosis, oxidative stress, and mutagenesis

2008 ◽  
Vol 295 (4) ◽  
pp. L552-L565 ◽  
Author(s):  
A. A. Shvedova ◽  
E. Kisin ◽  
A. R. Murray ◽  
V. J. Johnson ◽  
O. Gorelik ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Carbon Nanotubes ◽  
Inflammatory Response ◽  
Single Walled Carbon Nanotubes ◽  
Mechanical And Thermal Properties ◽  
Single Walled Carbon ◽  
Pharmaceutical Industries ◽  
Walled Carbon Nanotubes ◽  
Pharyngeal Aspiration ◽  
Granulomatous Pneumonia

Nanomaterials are frontier technological products used in different manufactured goods. Because of their unique physicochemical, electrical, mechanical, and thermal properties, single-walled carbon nanotubes (SWCNT) are finding numerous applications in electronics, aerospace devices, computers, and chemical, polymer, and pharmaceutical industries. SWCNT are relatively recently discovered members of the carbon allotropes that are similar in structure to fullerenes and graphite. Previously, we ( 47 ) have reported that pharyngeal aspiration of purified SWCNT by C57BL/6 mice caused dose-dependent granulomatous pneumonia, oxidative stress, acute inflammatory/cytokine responses, fibrosis, and decrease in pulmonary function. To avoid potential artifactual effects due to instillation/agglomeration associated with SWCNT, we conducted inhalation exposures using stable and uniform SWCNT dispersions obtained by a newly developed aerosolization technique ( 2 ). The inhalation of nonpurified SWCNT (iron content of 17.7% by weight) at 5 mg/m3, 5 h/day for 4 days was compared with pharyngeal aspiration of varying doses (5–20 μg per mouse) of the same SWCNT. The chain of pathological events in both exposure routes was realized through synergized interactions of early inflammatory response and oxidative stress culminating in the development of multifocal granulomatous pneumonia and interstitial fibrosis. SWCNT inhalation was more effective than aspiration in causing inflammatory response, oxidative stress, collagen deposition, and fibrosis as well as mutations of K- ras gene locus in the lung of C57BL/6 mice.

Increasing the elongation at break of polyhydroxybutyrate biopolymer: Effect of cellulose nanowhiskers on mechanical and thermal properties

2012 ◽  
Vol 127 (5) ◽  
pp. 3613-3621 ◽  
Author(s):  
Patrícia S. de O. Patrício ◽  
Fabiano V. Pereira ◽  
Meriane C. dos Santos ◽  
Patterson P. de Souza ◽  
Juan P. B. Roa ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Mechanical And Thermal Properties ◽  
Cellulose Nanowhiskers ◽  
Elongation At Break
Sign in / Sign up

Export Citation Format

Share Document