scholarly journals Novolac/Phenol-Containing Phthalonitrile Blends: Curing Characteristics and Composite Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 126 ◽  
Author(s):  
Hanqi Zhang ◽  
Bing Wang ◽  
Yanna Wang ◽  
Heng Zhou
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Mechanical Test ◽  
Gelation Time ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Hydroxyl Group ◽  
Rheological Analysis ◽  
Curing Characteristics ◽  
Ft Ir

The phenol-containing phthalonitrile resin is a kind of self-curing phthalonitrile resin with high-temperature resistance and excellent properties. However, the onefold phthalonitrile resin is unattainable to cured completely, and the brittleness of the cured product is non-negligible. This paper focuses on solving the above problems by blending novolac resin into phenol-containing phthalonitrile. Under the action of abundant hydroxyl group, the initial curing temperature and gelation time at 170 °C decrease by 88 °C and 2820 s, respectively, monitored by DSC and rheological analysis. FT-IR spectra of copolymers showed that the addition of novolac increased the conversion rate of nitrile. When the novolac mass fraction is 10%, the peak of nitrile group disappears, which means the complete reaction. The mechanical test of blends composites shows that the maximum fracture strain of 10 wt% novolac addition is 122% higher than those of neat phthalonitrile composites on account of the introduction of flexible novolac chain segments. The mechanical properties are sensitive to elevated post-cured temperature; this is consistent with the result of morphological investigation using SEM. Finally, the dynamic mechanical analysis indicated that the glass transition temperature heightened with the increase of novolac content and post-curing temperature.

Effect of Carbon Nanotube on Electrical, Thermal and Mechanical Properties of Epoxy

2007 ◽  
Author(s):  
Yuanxin Zhou ◽  
Peixuan Wu ◽  
Zhongyang Cheng ◽  
Biddut Kanti Dey ◽  
Shaik Jeelani
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Carbon Nanotube ◽  
High Speed ◽  
Mechanical Test ◽  
High Vacuum ◽  
Mechanical Analysis ◽  
Thermal And Mechanical Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Mechanical Agitator

In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CNTs) reinforced Epon 862 epoxy have been evaluated. Firstly, 0.1 wt%, 0.2 wt%, 0.3 wt%, and 0.4 wt% CNT were infused into epoxy through a high intensity ultrasonic liquid processor and then mixed with EpiCure curing agent W using a high speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using a high vacuum. Neat epoxy sample also was made as reference. Electrical conductivity, dynamic mechanical analysis (DMA, three point bending tests and fracture tests were performed on unfilled, CNT-filled epoxy to identify the loading effect on the properties of composites. Experimental results show significant improvement in electric conductivity. The resistivity of epoxy decreased to 15Ωm with 0.4% CNT. DMA studies revealed that filling the carbon nanotube into epoxy can produce a 90% enhancement in storage modulus and a 17° C increase in Tg, but CNT has little effect on decomposing temperature. Mechanical test results showed that modulus increased with higher CNT loading percentages, but the 0.3 wt% CNT-infusion system showed the maximum strength and fracture toughness enhancement. The decrease in strength and fracture toughness in 0.4% CNT/epoxy was attributed to poor dispersions of nanotubes in the composite.

Mechanical Properties of Coil Coating Evaluated with Dynamic Mechanical Analysis in Daul Cantilever

2007 ◽  
Vol 353-358 ◽  
pp. 1729-1732 ◽  
Author(s):  
Lei Chen ◽  
Hong Liang Pan
Keyword(s):  
Mechanical Properties ◽  
Dynamic Mechanical Analysis ◽  
Loss Modulus ◽  
Paint Layer ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Mode Analysis ◽  
Dynamic Mechanical ◽  
Preparation Conditions ◽  
Coil Coating

The storage modulus, loss modulus, loss tangent (tanδ), stress and strain have been determined for painted steel specimens by dynamic mechanical analysis (DMA) operated in Dual Cantilever mode. Analysis of the composite system enabled the elastic modulus of the paint layer to be calculated and the result can be useful to analyze the mechanical properties of the coil coating. The calculation was found to be very sensitive to the geometry (especially thickness of the substrate and coating) and properties of the substrate and coating, leading to considerable variability in the calculated coating modulus. The DMA method was successful in detecting the glass transition temperature (Tg) as a peak in the tanδ curve. The value of Tg is sensitive to the preparation conditions (e.g. curing temperature) and composition of the paint. The results show that DMA in Dual Cantilever can be useful as a characterization tool for painted steel.

Synthesis and properties of a novel high-temperature vinylpyridine-based phthalonitrile polymer

2018 ◽  
Vol 31 (7) ◽  
pp. 820-830 ◽  
Author(s):  
Haifeng Wang ◽  
Zhenjiang Zhang ◽  
Puguang Ji ◽  
Xiaoyan Yu ◽  
Kimiyoshi Naito ◽  
...  
Keyword(s):  
Complex Viscosity ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Gravimetric Analysis ◽  
Test Results ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Rheological Analysis ◽  
Dsc Analyses ◽  
Low Complex

A novel vinylpyridine-based phthalonitrile monomer, 2,6-bis[3-(3,4-dicyanophenoxy)styryl]pyridine (BDSP), was resoundingly produced by a nucleophilic substitution reaction of 2,6-bis(3-hydroxystyryl)pyridine with 4-nitrophthalonitrile in the presence of potassium carbonate. The chemical structure of the synthesized BDSP was confirmed by proton (1H) and carbon (12C) nuclear magnetic resonance (NMR) as well as Fourier transform infrared (FTIR) analysis. The curing behavior of BDSP was investigated by FTIR and differential scanning calorimetry (DSC) analyses. The resin showed a low complex viscosity in the wide processing window between the monomer melting temperature and the curing temperature of the polymer, as discovered by rheological analysis. In addition, the properties of the polymer were studied by thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Based on the test results, the BDSP polymer demonstrated superior processing performance, excellent thermal stability, outstanding mechanical properties, and low water uptake, and these advanced performance characteristics are critical to many fields.

scholarly journals Amino-Functionalized Lead Phthalocyanine-Modified Benzoxazine Resin: Curing Kinetics, Thermal, and Mechanical Properties

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1855 ◽  
Author(s):  
Li-wu Zu ◽  
Bao-chang Gao ◽  
Zhong-cheng Pan ◽  
Jun Wang ◽  
Abdul Qadeer Dayo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Kinetic Parameters ◽  
Curing Kinetics ◽  
Dynamic Mechanical Properties ◽  
Mechanical Analysis ◽  
Curing Temperature ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Dynamic Mechanical

Phenol-diaminodiphenylmethane-based benzoxazine (P-ddm)/phthalocyanine copolymer was prepared by using P-ddm resin as matrix and 3,10,17,24-tetra-aminoethoxy lead phthalocyanine (APbPc) as additive. Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA) were used to investigate the curing behavior, curing kinetics, dynamic mechanical properties, thermal stability, and impact strength of the prepared copolymers. The kinetic parameters for the P-ddm/APbPc blend curing processes were examined by utilizing the iso-conversional, Flynn–Wall–Ozawa, and Málek methods. The P-ddm/APbPc blends exhibit two typical curing processes, and DSC results confirmed that the blending of APbPc monomer can effectively reduce the curing temperature of P-ddm resin. The autocatalytic models also described the non-isothermal curing reaction rate well, and the appropriate kinetic parameters of the curing process were obtained. The DMA and impact strength experiments proved that the blending of APbPc monomer can significantly improve the toughness and stiffness of P-ddm resin, the highest enhancements were observed on 25 wt.% addition of APbPc, the recorded values for the storage modulus and impact strength were 1003 MPa and 3.60 kJ/m2 higher, respectively, while a decline of 24.6 °C was observed in the glass transition temperature values. TGA curves indicated that the cured copolymers also exhibit excellent thermal stabilities.

Effect of carbon fiber amount and length on flame retardant and mechanical properties of intumescent polypropylene composites

2017 ◽  
Vol 52 (4) ◽  
pp. 519-530 ◽  
Author(s):  
Lemiye Atabek Savas ◽  
Aysenur Mutlu ◽  
Ali Sinan Dike ◽  
Umit Tayfun ◽  
Mehmet Dogan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Carbon Fiber ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Mechanical Test ◽  
Mechanical Analysis ◽  
Limiting Oxygen Index ◽  
Polypropylene Composites ◽  
Index Value

The effects of carbon fiber amount and length were studied on the flame retardant, thermal, and mechanical properties of the intumescent polypropylene composites. The flame retardant properties of the intumescent polypropylene-based composites were investigated using limiting oxygen index, vertical burning test (UL-94), and mass loss calorimeter. The mechanical properties of the composites were studied using tensile test and dynamic mechanical analysis. According to the flammability tests results, the antagonistic interaction was observed between carbon fiber and ammonium polyphosphate. The limiting oxygen index value reduced steadily as the added amount of carbon fiber increased. Mechanical test results revealed that the addition of carbon fiber increased the tensile strength and the elastic modulus as the added amount increased. No effect of carbon fiber length was observed on the flammability, fire performance, and tensile properties of composites, whereas the elastic modulus increased as the carbon fiber initial length increased.

Crosslink density and mechanical property evolution during the curing of polyurethane-urea/sodium silicate hybrid composites

2021 ◽  
pp. 095400832110394
Author(s):  
Yong Sun ◽  
Anqi Yu ◽  
Yuntao Liang ◽  
Gang Wang ◽  
Shuanglin Song ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sodium Silicate ◽  
Crosslink Density ◽  
Hybrid Composites ◽  
Mechanical Test ◽  
Mechanical Analysis ◽  
Positive Influence ◽  
Curing Time ◽  
Test Results ◽  
Structure Property

In order to understand the evolution of the structure–property relationship between the crosslink density and mechanical properties of polyurethane-urea/sodium silicate (PU/SS) hybrid composites, a series of PU/SS composites with 2.5 wt% organofunctional silanes and pure PU/SS composites are investigated at different curing time. Mechanical properties, the fracture surface morphology, and thermo-mechanical properties of these PU/SS composites are characterized by electron omnipotence experiment machine, scanning electron microscope, and dynamic mechanical analysis (DMA), respectively. The mechanical test results show the strength and fracture toughness of the PU/SS composites first increase and then stabilize during cure, and the modification leads to PU/SS composites with significantly higher mechanical properties. Further, the morphology of fractured samples also reveals that the longer curing time and the modification of the PU/SS composites means a higher curing degree. Moreover, the increase in the crosslink density calculated from the DMA tests quantitatively confirmed the positive influence of the curing time and the modification in enhancing mechanical properties. In addition, it is also found that the mechanical properties of the PU/SS composites not only depend on the crosslink density but also on the well-dispersed hybrid PU/SS system.

Effect of Activator Concentration on the Properties of Metakaolin-Based Geopolymer

2019 ◽  
Vol 11 (11) ◽  
pp. 1566-1573
Author(s):  
Chao Cui ◽  
Zhen Liu ◽  
Jianren Zhang ◽  
Chunsheng Cai ◽  
Hui Peng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Dispersive Spectrometer ◽  
Curing Temperature ◽  
Activator Concentration ◽  
Reaction Products ◽  
Sem Images ◽  
Homogeneous Matrix ◽  
Ft Ir ◽  
Alkaline Activator

In the present study, an alkaline solution, prepared by sodium silicate (Na2SiO3) and sodium hydroxide (NaOH), was used as an activator for the preparation of a metakaolin-based geopolymer with high compressive strength. The effects of the factors, including the modulus (SiO2/Na2O ratio) of the alkaline activator, activator concentration, curing temperature, and curing time on the mechanical properties of the geopolymer were examined using orthogonal tests. Test results showed that the concentration of the alkaline activator is the primary factor affecting the mechanical properties of the geopolymer, followed by the modulus of the alkaline activator. The compressive strength of the geopolymer increases with an increase in activator concentration and decrease in the modulus of the alkaline activator. Subsequently, the reaction degree of the geopolymer and the reaction products corresponding to various concentrations of the activator were investigated using microcalorimetric analysis, Fourier Transform Infrared (FT-IR) analysis, and Scanning electron microscopy-Energy Dispersive Spectrometer (SEM-EDS) analysis, and the mechanism of the activator concentration affecting the geopolymer properties was also studied. It was found that the hydrolysis reaction and the polymerization degree were improved with an increase in the activator concentration. When the activator concentration increased from 50% to 80%, the compressive strength of the geopolymer increased from 21.54 MPa to 99.89 MPa. In addition, the SEM images also showed that the reaction products with a higher activator concentration, had a denser and more homogeneous matrix than that of products with a lower activator concentration.

scholarly journals Differences of Curing Effects between a Human and Veterinary Bone Cement

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 470 ◽  
Author(s):  
K. Kallol ◽  
M. Motalab ◽  
M. Parvej ◽  
P. Konari ◽  
H. Barghouthi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Mechanical Behavior ◽  
Bone Cement ◽  
Curing Temperature ◽  
Interface Fracture ◽  
Curing Time ◽  
Curing Conditions ◽  
Curing Characteristics ◽  
Significant Difference

The goal of the study is to understand how the curing characteristics of a human bone cement (HBC) and veterinary bone cement (VBC) influence the mechanical behavior of each cement and cement bonding with an implant. This study hypothesizes that the curing temperature and time influence the mechanical properties of the cement adjacent to the implant, which resulted in the variability in bonding strength between the implant and cement. To test this hypothesis, this study measured the exothermic temperature, flexural strength, hardness, and morphology of a HBC and VBC at different curing times. In addition, this study measured shear strength at the interfaces of implant/HBC and implant/VBC samples during static and stepwise cyclic tests at different curing times. This study used Stryker Simplex P and BioMedtrix 3 poly methyl methacrylate (PMMA) as an HBC and VBC, respectively. This study cured HBC and VBC cement for 30 and 60 min and then conducted flexural, hardness, and interface fracture tests to evaluate the curing effect on mechanical behavior of each of the cements. This study found that the curing time significantly increases the values of flexure and hardness properties of each cement and shear strength of implant/HBC and implant/VBC (p < 0.05). This study observed a difference of curing time and temperature between HBC and VBC. This study also observed a significant difference of surface porosity at the interface of implant/HBC and implant/VBC interfaces. The variability of mechanical properties between HBC and VBC due to the differences of curing conditions may influence the bonding of cement with the implant.

Effect of Fiber Surface Modification with Different Functional Groups Silane Agents on Mechanical Properties of Hemps/Polypropylene Composites

2013 ◽  
Vol 470 ◽  
pp. 23-26 ◽  
Author(s):  
Hong Chang Han ◽  
X. Lu Gong
Keyword(s):  
Mechanical Properties ◽  
Fracture Strain ◽  
Fiber Surface ◽  
Covalent Bond ◽  
Tensile Tests ◽  
Hemp Fiber ◽  
Polypropylene Composites ◽  
Propyl Methacrylate ◽  
Ft Ir ◽  
Sem Morphology

In this paper, we firstly treated the hemp fiber with alkali solution, followed by chemical modification with silane agents: 3-(Trimethoxysilyl) propyl methacrylate (MPS), N-[3-(Trimethoxysilyl) propyaniline (PAPS) and (3-Aminopropyl) triethoxysilane (APS), respectively. These treated fibers were then blended with polypropylene (PP). SEM morphology and FT-IR spectra confirmed the successful modifications of MPS, PAPS and APS with hemp fiber. The tensile tests results showed that APS improved the mechanical properties of composite, due to the amino of APS could react with maleic anhydride forming amide covalent bond which is benefit in the stress transferring from PP matrix to fiber. In contrast, since the incompatibility of aniline with propylene, PAPS modification decreased the fracture stress composites. The existences of ester and vinyl groups in MPS contributed to the increase of composite fracture strain caused by chain slips.

scholarly journals MEASUREMENTS OF RHEOLOGYCAL AND MECHANICAL-, THERMO-MECHANICAL PROPERTIES OF PVC/CORN COB FOAM COMPOSITE

2017 ◽  
Vol 5 (10) ◽  
pp. 313-321
Author(s):  
Krisztina Roman ◽  
Gabriella Zsoldos
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Mechanical Analysis ◽  
Corn Cob ◽  
Rheological Analysis ◽  
Structures And Properties ◽  
Foam Composite ◽  
The Relationship ◽  
And Diffusion ◽  
Diffusion Properties

In this paper, the modification of PVC/Corn cob blends was investigated. Rheological and diffusion properties of blends are important to learn the behavior of blend’s in molten state, because it will provide information necessary for the processing. Nowadays, the development of biomaterials has become a primary goal for material engineers. Using materials from natural sources gives an option to modify PVC structures and properties. The following mechanical properties of the prepared composite were determined; tensile-, bending strength and hardness. The PVC/Corn cob blends have increased impact strength and the other mechanical properties can be improved as well. The relationship between the morphology and properties of the foam were also investigated. The result of DSC and dynamic mechanical analysis showed that the blends form a partially compatible system. The rheological analysis showed that the PVC composite with corn cob could be processed and recycled using regular thermoplastic processing systems.

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