Relationship between crystalline structure of polyamide 6 within carbon fibers and their mechanical properties studied using Micro-Raman spectroscopy

Polymer ◽  
2021 ◽  
Vol 223 ◽  
pp. 123711
Author(s):  
Hideyuki Uematsu ◽  
Takahiro Kawasaki ◽  
Koutarou Koizumi ◽  
Ayaka Yamaguchi ◽  
Shinji Sugihara ◽  
...  
2017 ◽  
Vol 898 ◽  
pp. 2134-2142
Author(s):  
Yu Fei Hu ◽  
Jian Zhang ◽  
Biao Wang ◽  
Xue Na Zhang

Unidirectional carbon fiber (CF) / Polyamide 6 (PA6) composites were prepared by stacking fabrics method. Due to the effect of the textile structure and rough surface of PA6 fabrics, slipping of carbon fibers (CFs) during the stacking process was prevented and uniformity of impregnation was improved. Meanwhile, the usage of PA6 fabrics resulted in the minimum level of void content of composites, which improved the mechanical properties of composites. Additionally, the void content of materials was associated with the mechanical properties of composites. The flexural strength of composite reached 819.58 MPa when its void content was 3.49%. Moreover, a model based on Darcy’s law was developed to simulate the impregnation behavior of PA6 in CFs which was made by stacking fabrics method. The resin flow was observed by using optical microscopy. The evolution of void content in composites was related to the processing parameters (holding time, processing temperature and processing pressure).The comparison between the experimental and simulated data showed that the model was reliable to describe the impregnation process.


RSC Advances ◽  
2016 ◽  
Vol 6 (109) ◽  
pp. 107739-107747 ◽  
Author(s):  
Lin Sang ◽  
YuKai Wang ◽  
Guangyi Chen ◽  
Jicai Liang ◽  
Zhiyong Wei

The silane-treated carbon fiber induced the formation of transcrystalline structure and enhanced the interfacial adhesion between the fiber and polyamide 6 matrix.


2010 ◽  
Vol 645-648 ◽  
pp. 315-318
Author(s):  
Nadeemullah A. Mahadik ◽  
Robert E. Stahlbush ◽  
Syed B. Qadri ◽  
Orest J. Glembocki ◽  
Dimitri A. Alexson ◽  
...  

The structure of various inclusions in SiC epitaxial layers grown on 4o offcut substrates was investigated using three advanced techniques. Using micro-Raman spectroscopy, the observed inclusions exhibited a complex structure having either different SiC polytypes like 3C or 6H or they were misoriented 4H-SiC inclusions. The UVPL images showed dislocations and other extended defects around the inclusion-related defects, and strain fields were observed in the x-ray topographs near the defect sites. Spectral UVPL imaging shows features with varying luminescence inside the inclusion related defects which propagate and may cause deformation in the crystalline structure and lead to non-radiative recombination centers within the defect.


2019 ◽  
Vol 50 (5) ◽  
pp. 665-673 ◽  
Author(s):  
Xin Qian ◽  
Xuefei Wang ◽  
Junjun Zhong ◽  
Jianhai Zhi ◽  
Fangfang Heng ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1903
Author(s):  
Abdullah S. Aljamhan ◽  
Mohammad H. Alrefeai ◽  
Alhanouf Alhabdan ◽  
Sarah A. Alhusseini ◽  
Imran Farooq ◽  
...  

The study aimed to analyze the effect of the addition of nano-hydroxyapatite (nano-HA) particles on the mechanical properties of experimental adhesive (EA). Furthermore, dentin interaction of EA (without nano-HA) and EA with nano-HA (hereon referred to as HA-10%) were also investigated and equated. Methods consisting of scanning electron microscopy (SEM)–energy-dispersive X-ray spectroscopy (EDX), micro-Raman spectroscopy, micro-tensile bond strength (µTBS) test, and Fourier transform infrared (FTIR) spectroscopy were employed to study nano-HA particles shape, dentin bond strength, degree of conversion (DC), and adhesive–dentin interaction. Ninety teeth (N = 90) were collected, and pre-bonding, conditioning of dentin was performed utilizing phosphoric acid (H3PO4) etching, photodynamic therapy (PDT), and ER-CR-YSGG (ECY) laser. The teeth were set to form bonded specimens using two adhesives. Nano-HA particles were spherical-shaped, and EDX confirmed the presence of oxygen, calcium, and phosphorus. Micro-Raman spectroscopy revealed distinct phosphate and carbonate peaks for nano-HA. The µTBS test demonstrated highest values for HA-10% group on the H3PO4 conditioned dentin. The greatest DC was observed for the EA group. The addition of nano-HA-10 wt.% particles in dentin adhesive resulted in improved bond strength. The incorporation also demonstrated acceptable DC (although lower than EA group), suitable dentin interaction, and resin tag formation.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2418
Author(s):  
Mohammad H. AlRefeai ◽  
Eman M. AlHamdan ◽  
Samar Al-Saleh ◽  
Imran Farooq ◽  
Eisha Abrar ◽  
...  

Our study aimed to synthesize and compare the mechanical properties and dentin interaction of two adhesives; experimental adhesive (EA) and EA containing 5 wt.% calcium fluoride (CaF2) nano-crystals (CaF2 adhesive-CAFA). CaF2 nano-crystals were synthesized by reacting two solutions (containing calcium and fluoride) in a glass chamber using a heated air system. The EA was produced using a mix of monomers, photo-initiators, camphorquinone, and electron initiators. The synthesized CaF2 nano-crystals were centrifuged to guarantee that inside the adhesive there is homogenized dispersion of the filler particles. Their integration in the EA yielded two groups; Gp-1: EA (without CaF2, control) and Gp-2: (5 wt.% CaF2 containing adhesive, CAFA). Sixty teeth were prepared and set to form bonded specimens using the two adhesives. The CaF2 nano-crystals were irregularly shaped with an average particle size of 30–200 nm. The highest μTBS values were obtained for CAFA-non-thermocycled (NTC) samples (32.63 ± 3.15), followed by EA-NTC (31.80 ± 3.75) specimens. On thermocycling (TC), both adhesive groups presented lower μTBS values (CAFA-TC: 29.47 ± 3.33 and EA-TC: 24.04 ± 3.69). Hybrid layer (HL) formation and resin tags of varying depths were perceived for both adhesive groups. The EDX analysis demonstrated the presence of carbon (C), silica (Si), calcium (Ca), and fluoride (F) for CAFA group. Micro-Raman spectroscopy revealed distinct peaks for CaF2 nano-crystals. The CAFA group presented the greatest DC. The addition of CaF2 nano-crystals in the adhesive caused improved bond μTBS and DC. The incorporation also demonstrated suitable dentin interaction, depicted by appropriate HL and resin tag development.


Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2855
Author(s):  
Mohammad H. AlRefeai ◽  
Eman M. AlHamdan ◽  
Samar Al-Saleh ◽  
Abdulaziz S. Alqahtani ◽  
Mohammad Q. Al-Rifaiy ◽  
...  

The study aimed at synthesizing β-tricalcium phosphate (β-TCP) nanoparticles and comparing the mechanical properties and dentin interaction of two adhesives: experimental adhesive (EA) and EA with 5 wt.% β-TCP nanoparticles (β-TCP-5%). These filler nanoparticles were synthesized and then characterized with scanning electron microscopy (SEM) and micro-Raman spectroscopy. The β-TCP nanoparticles were incorporated in the adhesives to form two groups: gp-1: EA (control) and gp-2: β-TCP-5%. These adhesives were characterized by SEM, energy-dispersive X-ray (EDX) spectroscopy and were also assessed for their micro-tensile bond strength (μTBS) with (TC) and without thermocycling (NTC). Fourier Transform Infrared (FTIR) spectroscopy was performed to evaluate the degree of conversion (DC) of two adhesives. The β-TCP filler was seen as irregularly shaped agglomerates on SEM. The micro-Raman spectra revealed characteristic peaks associated with β-TCP nanoparticles. Both adhesives presented suitable dentin interaction, which was demonstrated by the formation of resin tags of variable depths. The EDX analysis verified the existence of calcium (Ca) and phosphate (P) for the β-TCP-5% group. The greatest μTBS values were shown by β-TCP-5% group samples when they were non-thermocycled (NTC) (β-TCP-5%-NTC: 34.11 ± 3.46) followed by the thermocycled (TC) samples of the same group (β-TCP-5%-TC: 30.38 ± 3.66), compared with the EA group. Although the DC presented by β-TCP-5% group was comparable to the EA group, it was still lower. The addition of β-TCP nanoparticles in the adhesive improved its μTBS and resulted in a suitable dentin interaction, seen in the form of hybrid layer and resin tag formation. Nonetheless, a decreased DC was observed for the β-TCP-5% adhesive. Future studies probing the effect of different filler concentrations on various properties of the adhesive are warranted.


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