Sequential Modification of ADMET Polyketone via Oxime Chemistry and Electrophilic Alkoxyetherification

2018 ◽  
Vol 71 (6) ◽  
pp. 449 ◽  
Author(s):  
Fu-Rong Zeng ◽  
Qi-Lin Zhu ◽  
Zi-Long Li

Post-polymerization modification is a facile and efficient method for the generation of diverse functional polymers. Herein, polymer-based molecular arrays were obtained by using sequential modification. First, periodic polyketone P0 was synthesized via acyclic diene metathesis (ADMET) polymerization of α,ω-diene M0. Oxime chemistry was employed in the functionalization of the ketone moieties of P0 using three commercially available alkoxyamine hydrochlorides. Finally, electrophilic alkoxyetherification, a four-component reaction, was employed in the modification of alkene groups on polymer main chains using N-bromosuccinimide (NBS), tetrahydrofuran, and fluorinated carboxylic acid. Complete conversion of reactive sites was observed in both steps, and the two modification reactions exhibited excellent compatibility. The thermal properties of the polymers as thermal stability, and glass transition and melting behaviours were investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC).

2017 ◽  
Vol 24 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Varun Mittal ◽  
Shishir Sinha

AbstractThe present paper deals with a study of the thermal properties of bagasse fiber (BF)-reinforced epoxy composites. BFs are subjected to untreated and chemical treatments with 1% sodium hydroxide followed by 1% acrylic acid at ambient temperature before the composites are made. The thermal stability of the components was studied by thermogravimetric analysis and differential scanning calorimetry, as well as by differential thermal gravimetric analysis. Thermal analysis results of untreated BF-reinforced epoxy composite were compared with treated BF-reinforced epoxy composite. The chemical treatment of BF induces reasonable changes in the thermal stability of the polymer composites.


1994 ◽  
Vol 6 (3) ◽  
pp. 249-256 ◽  
Author(s):  
D G Hawthorne ◽  
J H Hodgkin ◽  
M B Jackson ◽  
T C Morton

The use of 2,2-bis(4-[(2-carboxy-5-furyl)oxy]phenyl)propane as a Diels-Alder based co-reactant for curing bismaleimides was investigated. Differential scanning calorimetry and thermal gravimetric analysis were used to study the thermal behaviour of this reactant on its own and in the presence of 1,1'-(4methylene-4,1-phenylene)bismaleimide. The range of products formed under different cure conditions was determined by vFnR spectroscopy. The DMTA characteristics and thermal stability of cured laminates made from this resin system have been investigated. It is concluded that the thermal stability and other properties of laminates made from this system are only comparable to those of a typical commercial bismaleimide system.


2012 ◽  
Vol 554-556 ◽  
pp. 126-129 ◽  
Author(s):  
Shun Yin ◽  
Ning Sun ◽  
Chun Yun Feng ◽  
Zhi Mou Wu ◽  
Zhao Hua Xu ◽  
...  

A series of different generation hyperbranched polyurethane(HBPU) was synthesized based on the raw materials of isophorone diisocyanate(IPDI) and diethanolamine(DEOA). Their structure, thermal degradation mechanism and glass transition temperature(Tg) were characterized by fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance spectroscopy(NMR), thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC). The results showed that: the yield of each generation HBPU was up to 90%, different generation HBPU had almost the same initial degradation temperature(about at 200°C) and they all had two decomposition platforms; with the increase of generation, Tg increased from 107.2°C to 132.1°C. The gloss and hardness of the HBPU coatings were significantly improved.


2020 ◽  
Vol 990 ◽  
pp. 106-110
Author(s):  
Mohd Zulkifli Mohamad Noor ◽  
Mohamad Anas Mohd Azmi ◽  
Mohd Shaiful Zaidi Mad Desa ◽  
Mohd Bijarimi Mat Piah ◽  
Azizan Ramli

Neoprene reinforced polymer has become an attraction in current research and development of new material blend. In this invention, neoprene was chosen to be enhance to polyurethane because of their superior properties that possess extraordinary mechanical, electrical, optical and thermal properties on prosthetic foot. In this research, polyurethane was chosen due to good rigidity, easy processing and low cost. The reinforcement polyurethane with neoprene is expected to improve the properties of polyurethane. The objective of this research was conducted to investigate the effect of neoprene contents on thermal properties of polyurethane reinforced neoprene on prosthetic foot. The effect of neoprene on thermal properties neoprene reinforced polyurethane was analysed in term of its thermal stability by thermal gravimetric analysis (TGA). Moreover, the visual of small topographic details on the surface of polyurethane/neoprene blends will be examined by scanning electron microscope (SEM). Based on result, the thermal properties show the great enhancement at high neoprene contents which is 1.0wt%. The thermal stability of polyurethane reinforced neoprene improves when the temperature where decomposition starts to occurs are higher than decomposition temperature of pure polyurethane. Then, thermal conductivity of polyurethane shows the great improvement after the addition of neoprene. Lastly, the smooth surface and visible of sheets pattern on surface represent the present of neoprene disperse into polymer that enhance brittleness. Thus, the presence of neoprene has clearly enhanced the thermal stability of the polyurethane. Table 1 shows formulation of neoprene and polyurethane.


2011 ◽  
Vol 23 (7) ◽  
pp. 513-517 ◽  
Author(s):  
Mohsen Ghorbani ◽  
Mohammad Soleimani Lashkenari ◽  
Hossein Eisazadeh

This study investigated the preparation and properties of polyaniline/silver (PAn/Ag2O) nanocomposite in aqueous media by chemical polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidant. The products were investigated in terms of morphology, chemical structure, thermal stability and thermal degradation using scanning electron microscopy, Fourier transform infrared, thermal gravimetric analysis and differential scanning calorimetry, respectively. The results indicated that the properties of products were dependent on the nanocomposite structure.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2636
Author(s):  
Tomasz M. Majka ◽  
Oskar Bartyzel ◽  
Konstantinos N. Raftopoulos ◽  
Joanna Pagacz ◽  
Krzysztof Pielichowski

Pyrolysis of the polypropylene/montmorillonite (PP/OMMT) nanocomposites allows for recovery of the filler that can be then re–used to produce PP/pyrolyzed MMT (PMMT) nanostructured composites. In this work, we discuss the thermal properties of PP/PMMT composites investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It has been found that effect of PMMT (5 wt. % and 10 wt. %) on matrix thermal stability occurs at temperatures above 300 °C. Addition of 5 wt. % and 10 wt. % of PMMT into polypropylene system gave good stabilization effect, as confirmed by the overall stabilization effect (OSE) values, which increased by 4% and 7%, respectively, compared to the control sample (PP). Interestingly, the presence of 1 wt. % and 3 wt. % of pyrolyzed clay stabilizes the system better than the same concentrations of organoclay added into polypropylene melt. DSC data revealed that pyrolyzed clay has still the same tendency as organoclay to enhance formation of the α and β crystalline PP phases only. The pyrolyzed MMT causes an improvement of the modulus in the glassy as well as rubbery regions, as confirmed by DMA results.


2013 ◽  
Vol 668 ◽  
pp. 259-262
Author(s):  
Ding Jun Zhang ◽  
Chao Yun Qu ◽  
Yu Xian Chen

The facile synthesis of two new Ionic electroconductive polyurethanes with the framework of ionic liquids, i.e., PUR-T: synthesized with isocyanate TDI; PUR-H: synthesized with isocyanate HDL, are described. Their structures and properties were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC) and the surface resistance meter. The effects of the different kinds of isocyanate on electrical conductivity of PUR were also investigated. It was found that their electrical conductivity can be optimized by changing the reaction temperature. The PUR-H, which exhibits an electrical conductivity of 1.0×104 Ω surface resistance, could be obtained in high yield, up to 65% at 90 oC for 12h.


2016 ◽  
Vol 29 (10) ◽  
pp. 1139-1147 ◽  
Author(s):  
Zi Sang ◽  
Tiantian Feng ◽  
Wenbin Liu ◽  
Jun Wang ◽  
Mehdi Derradji

A new series of aniline and aniline-mixed tetrafunctional fluorene-based oxazine monomers were synthesized using 2,7-hydroxy-9,9-bis-(4-hydroxyphenyl) fluorene, paraformaldehyde, and primary amines (including aniline or aniline mixed with n-butylamine or n-octylamine composition). Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy were used to characterize the structure of the monomers. The copolymers were obtained by adding the monomers into a typical monofunctional polybenzoxazine (phenol-aniline-based benzoxazine). Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis were performed to study the thermal properties of the copolymers. The copolymers exhibited high glass transition temperature values (164–201°C). A good thermal stability was also obtained with a 5% weight loss temperature over 355°C and high char yields at 800°C (42–50%).


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3171-3185
Author(s):  
Perry Law Nyuk Khui ◽  
Rezaur Rahman ◽  
Abu Saleh Ahmed ◽  
Kuok King Kuok ◽  
Muhammad Khusairy Bin Bakri ◽  
...  

The morphological and thermal properties of composites containing a bioplastic blend and micro/nano-sized biochar from pyrolyzed jatropha seeds from microwave pyrolyzed jatropha seeds were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The biocomposite samples exhibited a brittle structure with a slightly ductile chip-like appearance. The Fourier transform infrared spectroscopy results for the PLA/PEMA/BC bio-composites were comparable to the PLA/BC biocomposites. A lower bio-filler content had more pronounced peak intensities than the higher bio-filler content biocomposites. The added PEMA compatibilizer in the PLA/PEMA/BC biocomposite showed more pronounced peaks, which indicated slightly improved bonding/interaction between the bio-filler and the matrix. Overall, increasing bio-filler content did not drastically affect the functional groups of the biocomposites. Thermogravimetric and differential scanning calorimetry analysis showed the developed biocomposites had a slight improvement in thermal stability, in comparison to the PLA sample. Improvements in the thermal stability of the PLA/PEMA/BC biocomposite could be attributed to the additional hydroxyl group, which was due to the added PEMA in the PLA and PLA/BC. According to the results of the analysis of the developed biocomposites, the biocomposites were more brittle and had reasonable thermal stability.


2003 ◽  
Vol 767 ◽  
Author(s):  
A. Tregub ◽  
G. Ng ◽  
M. Moinpour

AbstractSoak of polyurethane-based CMP pads in tungsten slurry and de-ionized water and its effect on retention of thermal and mechanical properties of the pads was studied using Dynamic Mechanical Analysis (DMA), Thermal Mechanical Analysis (TMA), Thermal Gravimetric Analysis (TGA), and Modulated Differential Scanning Calorimetry (MDSC). Simultaneous cross-linking and plastisizing due to soak were established using DMA and MDSC analysis. The stable operating temperature range and its dependence on soak time were determined using TMA analysis. Substantial difference in diffusion behavior of the “soft” and “hard” pads was discovered: diffusion into the hard pads followed Fickian law [1], while diffusion into the multi-layer soft pads was dominated by the fast filling of the highly porous pad surface with liquid.During a traditional CMP process, which involves application of polishing pads and slurry, the pad properties can be substantially and irreversibly changed as the result of slurry/rinse water absorption.The retention of the pad properties after exposure was monitored using such thermal and mechanical techniques, as Thermal Mechanical Analysis (TMA), Dynamical Mechanical Analysis (DMA), Modulated Differential Scanning Calorimetry (MDSC), Thermal Gravimetric Analysis (TGA).


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