Study on the modification of hexamethylenediamine-phenol-based polybenzoxazine resins by halloysite nanotubes

2019 ◽  
Vol 31 (9-10) ◽  
pp. 1204-1216 ◽  
Author(s):  
Jing Li ◽  
Zhiqiang Shen ◽  
Li Xu ◽  
Huaijun Song ◽  
Gang Guan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silane Coupling Agent ◽  
Succinic Anhydride ◽  
Halloysite Nanotubes ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Silane Coupling ◽  
Flexural Tests ◽  
Thermal Stability Of

In this study, hexamethylenediamine-phenol-based benzoxazine monomer (Ba-h) was synthesized using 1,6-hexamethylenediamine, phenol, and paraformaldehyde. Halloysite nanotubes (HNTs) were treated with silane coupling agent and succinic anhydride, respectively. Then the pristine and grafted HNTs were used as nano-fillers to modify Ba-h at different mass ratios ranging between 0 and 2.5 wt% via solution processing. Nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared spectroscopy confirmed the molecular structure of the monomer. The curing behaviors of the nanocomposites were examined by differential scanning calorimetry (DSC). The results of DSC, thermogravimetric analysis, and dynamic mechanical analysis displayed the obvious improvement in the thermal stability of the nanocomposites modified by the grafted HNTs. The results of impact and flexural tests revealed the improvement in the mechanical property of the nanocomposites modified by the pristine HNTs. These enhancements are related to the homogeneous dispersion of HNTs based on the scanning electron microscopy and transmission electron microscopy results.

scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

Preparation, characterization, and properties of polystyrene/Na-montmorillonite composites

2018 ◽  
Vol 32 (8) ◽  
pp. 1078-1091 ◽  
Author(s):  
Sibel Erol Dağ ◽  
Pınar Acar Bozkurt ◽  
Fatma Eroğlu ◽  
Meltem Çelik
Keyword(s):  
Electron Microscopy ◽  
Interlayer Spacing ◽  
Decomposition Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Specific Pore Volume ◽  
Transmission Electron ◽  
Thermal Stability Of

A series of polystyrene (PS)/unmodified Na-montmorillonite (Na-MMT) composites were prepared via in situ radical polymerization. The prepared composites were characterized using various techniques. The presence of various functional groups in the unmodified Na-MMT and PS/unmodified Na-MMT composite was confirmed by Fourier transform infrared spectroscopy. Morphology and particle size of prepared composites was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). According to the XRD and TEM results, the interlayer spacing of MMT layers was expanded. SEM images showed a spongy and porous-shaped morphology of composites. TEM revealed the Na-MMT intercalated in PS matrix. The thermal stability of PS/unmodified Na-MMT composites was significantly improved as compared to PS, which is confirmed using thermogravimetric analysis (TGA). The TGA curves indicated that the decomposition temperature of composites is higher at 24–51°C depending on the composition of the mixture than that of pure PS. The differential scanning calorimetry (DSC) results showed that the glass transition temperature of composites was higher as compared to PS. The moisture retention, water uptake, Brunauer–Emmett–Teller specific surface area, and specific pore volume of composites were also investigated. Water resistance of the composites can be greatly improved.

scholarly journals Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Chern Chiet Eng ◽  
Nor Azowa Ibrahim ◽  
Norhazlin Zainuddin ◽  
Hidayah Ariffin ◽  
Wan Md. Zin Wan Yunus ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Polylactic Acid ◽  
Mechanical Analysis ◽  
Basal Spacing ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Thermal Stability Of

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

Preparation and characterization of poly(ethylene 2,5-furandicarboxylate/nanocrystalline cellulose composites via solvent casting

2017 ◽  
Vol 37 (9) ◽  
pp. 869-878 ◽  
Author(s):  
Amandine Codou ◽  
Nathanaël Guigo ◽  
Jesper Gabriël van Berkel ◽  
Ed de Jong ◽  
Nicolas Sbirrazzuoli
Keyword(s):  
Electron Microscopy ◽  
Crystallization Temperature ◽  
Nanocrystalline Cellulose ◽  
Solvent Casting ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Cellulose Composites ◽  
Poly Ethylene ◽  
Thermal Stability Of

AbstractThe effect of nanocrystalline cellulose dispersion on the nonisothermal crystallization of poly(ethylene 2,5-furandicarboxylate) (PEF) has been investigated by means of solvent casting. The cellulose dispersion plays a significant role on the crystallization temperature, thus dispersive equipments of increasing energies were employed to improve the cellulose particles disaggregation. Therefore, ultra-sonic bath, ultra-sonication, and ultra-turrax were used to disperse cellulose nanocrystals in 1,1,1,3,3,3-hexafluoro-2-propanol. Dissolved separately in the same solvent, PEF was then poured into the cellulose suspension before casting. The cellulose whiskers were inspected by transmission electron microscopy. Differential scanning calorimetry was used to measure the crystallization temperature, while scanning electron microscopy visualized the cellulose dispersion at the fracture surface. After investigation on the interaction of cellulose/PEF via Fourier transform infrared spectroscopy, the thermal stability of the blends was measured by means of thermogravimetric analysis.

Preparation of benzoxazine-modified halloysite nanotubes and its application on epoxy/benzoxazine composites

2020 ◽  
Vol 32 (10) ◽  
pp. 1122-1130 ◽  
Author(s):  
Zhiqiang Shen ◽  
Yun Liu ◽  
Jing Li ◽  
Li Xu ◽  
Guoji Liu
Keyword(s):  
Bisphenol A ◽  
Halloysite Nanotubes ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Diglycidyl Ether ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
Ternary Composite ◽  
Dispersion State ◽  
Thermal Stability Of

Benzoxazine monomer (named as B-aptes) was synthesized from 3-aminopropyltriethoxysilane (KH-550), bisphenol A (BPA), and paraformaldehyde. Subsequently, functionalized halloysite nanotubes were obtained by introducing B-aptes onto the surface of halloysite nanotubes (HNTs). Then, benzoxazine-modified halloysite nanotubes (B-HNTs) were used to combine with BPA epoxy resin to prepare the diglycidyl ether of bisphenol-A (DGEBA)/B-HNTs composites. The homogeneous dispersion state of modified HNTs in the cured composite matrix was observed by scanning electron microscopy. Differential scanning calorimetry was used to investigate polymerization behaviors of ternary composites. The results showed that the ternary composite possessed lower polymerization temperature compared with the neat DGEBA/benzoxazine. According to the results of thermogravimetric analysis, the thermal stability of DGEBA/benzoxazine copolymers was improved by the modified HNTs, the char yield increased with the increase of HNTs mass ratio. The results of mechanical tests and dynamic mechanical analysis displayed that the DGEBA/B-HNTs composites possessed promoted mechanical properties.

Thermal stability of CaCO3/polyethylene (PE) nanocomposites

2019 ◽  
Vol 27 (7) ◽  
pp. 371-382
Author(s):  
S Sahebian ◽  
MT Hamed Mosavian
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Morphological Structure ◽  
Thermomechanical Analysis ◽  
Scanning Calorimetry ◽  
Weight Percentage ◽  
Transmission Electron ◽  
Crystallization Experiments ◽  
Thermal Stability Of

Calcium carbonate (CaCO3) nanoparticles in polymer matrix cause to improvement in polymer performance, including thermal stability and mechanical properties. The main goal of this article is to investigate the effect of different weight percentage of nanoparticles of CaCO3 on thermal stability and mechanical properties of polyethylene (PE) nanocomposites. The morphological structure of CaCO3 nanoparticles and nanocomposites was investigated by transmission electron microscopy and scanning electron microscopy. The thermal stability of PE and its nanocomposites was also determined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis. Nonisothermal crystallization experiments by DSC test showed that the incorporation of nanoparticles increased the crystallinity, glass transition temperature, and the effective energy barrier for crystallization process. Besides, degradation behavior was evaluated by TGA. The onset mass loss temperature shifted to higher value in the presence of nanoparticles.

Light-cured dental composites characterization by Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 428-429
Author(s):  
B. M. Culbertson ◽  
M. L. Devinev ◽  
E. C. Kao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Service Performance ◽  
Dental Composite ◽  
Dental Composites ◽  
Neat Resin ◽  
Scanning Calorimetry ◽  
Research Meeting ◽  
Formulation Variables

The service performance of current dental composite materials, such as anterior and posterior restoratives and/or veneer cements, needs to be improved. As part of a comprehensive effort to find ways to improve such materials, we have launched a broad spectrum study of the physicochemical and mechanical properties of photopolymerizable or visible light cured (VLC) dental composites. The commercially available VLC materials being studied are shown in Table 1. A generic or neat resin VLC system is also being characterized by SEM and TEM, to more fully understand formulation variables and their effects on properties.At a recent dental research meeting, we reported on the differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) characterization of the materials in Table 1. It was shown by DSC and DMA that the materials are substantially undercured by commonly used VLC techniques. Post curing in an oral cavity or a dry environment at 37 to 50°C for 7 or more hours substantially enhances the cure of the materials.

scholarly journals Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2254
Author(s):  
Adeleke A. Oyekanmi ◽  
N. I. Saharudin ◽  
Che Mohamad Hazwan ◽  
Abdul Khalil H. P. S. ◽  
Niyi G. Olaiya ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Cellulose Nanofibrils ◽  
Hydroxyl Groups ◽  
Water Contact ◽  
Silane Coupling ◽  
Cnf Films ◽  
Kenaf Bast ◽  
Thermal Stability Of

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

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