Toughening effect and mechanism of polyamide 12 and modified montmorillonite in polybenzoxazine resin

2018 ◽  
Vol 38 (10) ◽  
pp. 933-943 ◽  
Author(s):  
Junping Zhou ◽  
Ruifang Wang ◽  
Xiaojia He ◽  
Chunxia Zhao ◽  
Haolan Gou ◽  
...  

AbstractThe mechanical properties of polybenzoxazine (PBa) resins were improved by adding polyamide 12 (PA12) and modified montmorillonite (OMMT) as additives. The mechanical properties and thermal stability of PBa and resulting PBa composites were investigated using an Instron universal material testing instrument and dynamic mechanical analysis. The morphologies of the fracture surfaces were characterized by scanning electron microscopy. The results of morphological studies showed that PBa/PA12/OMMT composites exhibit significantly improved mechanical properties and thermal stability compared with that of the pristine PBa. When the OMMT content increased to 1 wt%, the fracture toughness (1.36 MPa·m1/2) and the fracture energy (GIC, 315.76 J·m−2) of PBa/PA12/OMMT-1 composites increased by 67.9% and 181.4%, respectively, compared with those of the pristine PBa. The thermal stability properties demonstrated that the storage modulus and glass transition temperature (Tg) of PBa/PA12/OMMT composites gradually increased with the addition of OMMT particles. The scanning electron microscopy results indicated that PBa/PA12/OMMT composites possess a toughening mechanism of crack deflection, with a large bulk of voids and debonding induced by PA12 and OMMT clay particles. Moreover, the OMMT might provide microvoid nucleating sites at its surface to release constrains for shear yielding.

2017 ◽  
Vol 54 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Maria Adina Vulcan ◽  
Celina Damian ◽  
Paul Octavian Stanescu ◽  
Eugeniu Vasile ◽  
Razvan Petre ◽  
...  

This paper deals with the synthesis of polyurea and its use as polymer matrix for nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Two types of materials were obtained during this research, the first cathegory uses the polyurea as matrix and the second one uses a mixture between epoxy resin and polyurea. The nanocomposites were characterized by Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM) and Tensile Tests .The elastomeric features of nanocomposites were highlighted by the results which showed low value of Tg. Also higher thermal stability with ~40oC compared with commercial products (M20) were observed, but lower mechanical properties compared to neat polyurea.


2011 ◽  
Vol 197-198 ◽  
pp. 1100-1103
Author(s):  
Jian Li

A polyurethane/clay (PU/clay) composite was synthesized. The microstructure of the composite was examined by scanning electron microscopy. The impact properties of the composite were characterized by impact testing. The study on the structure of the composite showed that clays could be dispersed in the polymer matrix well apart from a few of clusters. The results from mechanical analysis indicated that the impact properties of the composite were increased greatly in comparison with pure polyurethane. The investigation on the mechanical properties showed that the impact strength could be obviously increased by adding 20 wt% (by weight) clay to the matrix.


2013 ◽  
Vol 652-654 ◽  
pp. 93-97 ◽  
Author(s):  
Jian Bing Guo ◽  
Kai Zhou Zhang ◽  
Dao Hai Zhang ◽  
Bin Wu ◽  
Min He ◽  
...  

The effects of polypropylene grafted with maleic anhydride (PP-g-MA) on the interfacial interaction of PP/GF composites were investigated by means of scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), and mechanical properties. The experimental results demonstrate that PP-g-MA could effectively improve interfacial interaction between the PP and LGF. Based on SEM, good interfacial adhesion between PP and LGF in PP/PP-g-MA/LGF(66.5/3.5/30) composites was observed. All results in this paper were consistent, and showed the good interaction between PP and LGF, which were proved by the mechanical properties of the composites.


2008 ◽  
Vol 47-50 ◽  
pp. 674-677 ◽  
Author(s):  
Poonsub Threepopnatkul ◽  
N. Kaerkitcha ◽  
N. Athipongarporn

This research is to study the properties of pineapple leaf fiber reinforced polycarbonate composites (PC/PALF). Surface of pineapple leaf fiber (PALF) was pre-treated with sodium hydroxide (PALF/NaOH) and modified with two different functionalities such as γ-aminopropyl trimethoxy silane (PALF/Z-6011) and γ-methacryloxy propyl trimethoxy silane (PALF/Z-6030). The effects of PALF content and chemical treatment were investigated by Fourier transform infrared spectroscopy, Scanning electron microscopy and mechanical testing. The modified pineapple leaf fibers composite also produces enhanced mechanical properties. Young’s modulus is highest in the case of the PALF/NaOH composites. The PALF/Z-6011 composites showed highest tensile strength and impact strength. In thermal property, the results from Thermogravimetric analysis showed that thermal stability of the composites is lower than that of neat polycarbonate resin and thermal stability decreased with increasing pineapple leaf fiber content.


Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.


2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.


2018 ◽  
Vol 186 ◽  
pp. 02001
Author(s):  
Teng-wei Zhu ◽  
Cheng-liang Miao ◽  
Zheng Cheng ◽  
Zhipeng Wang ◽  
Yang Cui ◽  
...  

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.


2009 ◽  
Vol 1187 ◽  
Author(s):  
Jakob R Eltzholtz ◽  
Marie Krogsgaard ◽  
Henrik Birkedal

AbstractBiology has evolved several strategies for attachment of sedentary animals. In the bivalves, byssi abound and the best known example being the protein-based byssus of the blue mussel and other Mytilidae. In contrast the bivalve Anomia sp. has a single calcified thread. The byssus is hierarchical in design and contains several different types of structures as revealed by scanning electron microscopy images. The mechanical properties of the byssus are probed by nanoindentation. It is found that the mineralized part of the byssus is very stiff with a reduced modulus of about 67 GPa and a hardness of ˜3.7 GPa. This corresponds to a modulus roughly 20% smaller than that of pure calcite and a hardness that is about 20% larger than pure calcite. The results reveal the importance of microstructure on mechanical performance.


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