scholarly journals Polydopamine-Modified Al2O3/Polyurethane Composites with Largely Improved Thermal and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1772 ◽  
Author(s):  
Ruikui Du ◽  
Li He ◽  
Peng Li ◽  
Guizhe Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
In Situ Polymerization ◽  
Mechanical Analysis ◽  
Thermal Interface Materials ◽  
Sem Images ◽  
Elongation At Break ◽  
Polyurethane Composites ◽  
Interface Materials

Alumina/polyurethane composites were prepared via in situ polymerization and used as thermal interface materials (TIMs). The surface of alumina particles was modified using polydopamine (PDA) and then evaluated via Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG), and Raman spectroscopy (Raman). Scanning electron microscope (SEM) images showed that PDA-Al2O3 has better dispersion in a polyurethane (PU) matrix than Al2O3. Compared with pure PU, the 30 wt% PDA-Al2O3/PU had 95% more Young’s modulus, 128% more tensile strength, and 76% more elongation at break than the pure PU. Dynamic mechanical analysis (DMA) results showed that the storage modulus of the 30 wt% PDA-Al2O3/PU composite improved, and the glass transition temperature (Tg) shifted to higher temperatures. The thermal conductivity of the 30 wt% PDA-Al2O3/PU composite increased by 138%. Therefore, the results showed that the prepared PDA-coated alumina can simultaneously improve both the mechanical properties and thermal conductivity of PU.

Influence of Acid-Treated Carbon Nano-Tubes on the Microstructure and Properties of Carbon Nano-Tubes Polyurethane Composites

2010 ◽  
Vol 146-147 ◽  
pp. 805-809
Author(s):  
Ji You Gu ◽  
Lan Zhang ◽  
Xian Kai Jiang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Acid Treatment ◽  
In Situ Polymerization ◽  
Mechanical Analysis ◽  
X Ray ◽  
Carbon Nano Tubes ◽  
Dynamic Storage ◽  
Treated Carbon ◽  
Polyurethane Composites

The investigations including the acid treatment to multi-walled carbon nano-tubes (MWNTs) and the synthesis of MWNTs/polyurethane composites via in situ polymerization were done. X-ray Photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA) were utilized for evaluating the effects of acid-treated MWNTs on the properties and microstructure of the composites. The results indicated that carboxyl groups could be successfully introduced onto the surface of MWNTs by acid treatment. The dynamic storage modulus and glass transition temperature of composites increased with the existence of MWNTs. The improvement of polyurethane by acid-treated MWNTs performed better compared to raw MWNTs.

Preparation and Characterization of In Situ Nanocomposites of Graphene Nanosheets/Polyurethane

2019 ◽  
Vol 814 ◽  
pp. 90-95 ◽  
Author(s):  
Guang Lei Lv ◽  
Yuan Yuan Li ◽  
Chen Fei ◽  
Zhi Hao Shan ◽  
Jing Gan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Graphene Nanosheets ◽  
Graphene Sheets ◽  
Microstructural Properties ◽  
Wear Performance ◽  
Polyurethane Composites

Graphene nanosheets/polyurethane (GNS/PU) was prepared in situ by polymerization technique for the manufacture of PU safety shoes soles. The graphene nanosheets/polyurethane composites were characterized for their mechanical properties, thermal conductivity and abrasion resistance, and comparison is made with those of the neat polyurethane. The microstructural properties of GNS/PU were characterized by SEM. The results show that with the increase of the amount of graphene within the range of weight-percentages analyzed, the tensile strength of the composites gradually increases. The tensile strength of the GNS/PU composites increased to 64.14 MPa with 2 wt% GNS, compared with 55.1 MPa for neat PU. When the graphene sheets reached 2 wt%, the abrasion volume reached 71 mm3. Compared with the pure PU, the wear performance of GNS/PU composites was significantly improved.

Mechanical Properties and Microstructure of PMMA-ZrO2 Nanocomposites for Dental CAD/CAM

2013 ◽  
Vol 785-786 ◽  
pp. 533-536 ◽  
Author(s):  
Shi Bao Li ◽  
Yi Min Zhao ◽  
Jian Feng Zhang ◽  
Cheng Xie ◽  
Dong Mei Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
In Situ Polymerization ◽  
Zirconia Ceramics ◽  
Sem Images ◽  
The Matrix ◽  
Cad Cam ◽  
Organic Resin

A novel PMMA-ZrO2 composite (PZC) was prepared by resin infiltrated to ceramic method. The composite mechanical properties were evaluated and correlated to its microstructure. Partially sintered zirconia ceramics (PSZC) were made by isostatic pressing and partially sintering. Subsequently, the PZC was prepared by vacuum infiltrating prepolymerized MMA into PSZC, followed by in-situ polymerization. When PSZC-70% was used as the matrix, the bending strength, elastic modulus, and fracture toughness of the prepared composite i.e PZC-70% were 202.56±12.09 MPa, 58.71±3.98 GPa, and 4.60±0.26 MPa·m1/2, corresponding to 25.69%, 23.31%, and 169.01% improvement, respectively, in comparison with the control matrix. Among them, the fracture toughness improvement was the most prominent. According to SEM images of the fracture surfaces, each pore of zirconia skeleton was filled by organic resin contributing to the bending strength improvement. These weak interfaces between zirconia skeleton and organic resin absorbed energy and terminated the growth of microcracks which might be responsible for significant improvement in fracture toughness. This PZC material is anticipated to be a new member of the dental CAD/CAM family.

Preparation and properties of nylon 6/sulfonated graphene composites by an in situ polymerization process

RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45014-45022 ◽  
Author(s):  
Chunhua Wang ◽  
Feng Hu ◽  
Kejian Yang ◽  
Tianhui Hu ◽  
Wenzhi Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
In Situ Polymerization ◽  
Nylon 6 ◽  
High Thermal Conductivity ◽  
Polymerization Process ◽  
Sulfonated Graphene

Nylon 6/sulfonated graphene composites with high thermal conductivity, good mechanical properties and excellent processability were prepared using sulfonated graphene as a precursor by an in situ polymerization process.

Estimation of Effective Thermal and Mechanical Properties of Particulate Thermal Interface Materials by a Random Network Model

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Pavan Kumar Vaitheeswaran ◽  
Ganesh Subbarayan
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Network Model ◽  
Random Network ◽  
Thermal Interface Materials ◽  
Thermal And Mechanical Properties ◽  
Thermal Interface ◽  
Classical Models ◽  
Interface Materials

Particulate thermal interface materials (TIMs) are commonly used to transport heat from chip to heat sink. While high thermal conductance is achieved by large volume loadings of highly conducting particles in a compliant matrix, small volume loadings of stiff particles will ensure reduced thermal stresses in the brittle silicon device. Developing numerical models to estimate effective thermal and mechanical properties of TIM systems would help optimize TIM performance with respect to these conflicting requirements. Classical models, often based on single particle solutions or regular arrangement of particles, are insufficient as real-life TIM systems contain a distribution of particles at high volume fractions, where classical models are invalid. In our earlier work, a computationally efficient random network model (RNM) was developed to estimate the effective thermal conductivity of TIM systems (Kanuparthi et al., 2008, “An Efficient Network Model for Determining the Effective Thermal Conductivity of Particulate Thermal Interface Materials,” IEEE Trans. Compon. Packag. Technol., 31(3), pp. 611–621; Dan et al., 2009, “An Improved Network Model for Determining the Effective Thermal Conductivity of Particulate Thermal Interface Materials,” ASME Paper No. InterPACK2009-89116.) . This model is extended in this paper to estimate the effective elastic modulus of TIMs. Realistic microstructures are simulated and analyzed using the proposed method. Factors affecting the modulus (volume fraction and particle size distribution (PSD)) are also studied.

Improving Study on Wear Resistance and Mechanical Properties of Graphene / Polyurethane Microfoam Composites

2021 ◽  
Vol 904 ◽  
pp. 226-231
Author(s):  
Guang Lei Lv ◽  
Xin Mei Liu ◽  
Ming Zhao ◽  
Yuan Yuan Li
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
In Situ Polymerization ◽  
Testing Machine ◽  
Universal Testing ◽  
Reduced Graphene ◽  
Polyurethane Composites ◽  
Polyurethane Nanocomposites ◽  
Scanning Electron

Modified reduced graphene oxide (rtgo) was prepared by using γ - isocyanate propyl triethoxysilane (IPTS) as modifier. Graphene / polyurethane nanocomposites were prepared by in-situ polymerization. Graphene / polyurethane composites were characterized by scanning electron microscopy, TGA, DIN abrasion and electronic universal testing machine. The effects of different reaction formulations and graphene addition on the wear resistance and mechanical properties of the composites were studied. The results show that the wear resistance and tear resistance of the composite can be greatly improved after the functional graphene is compounded with polyurethane.

scholarly journals Improvement of mechanical properties of HfB2-based composites by incorporating in situ SiC reinforcement through pressureless sintering

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Ghadami ◽  
E. Taheri-Nassaj ◽  
H. R. Baharvandi ◽  
F. Ghadami
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Relative Density ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
Vacuum Atmosphere ◽  
Sic Reinforcement ◽  
Microstructural Studies ◽  
Composite Samples

AbstractHfB2, Si, and activated carbon powders were selected to fabricate 0–30 vol% SiC reinforced HfB2-based composite. Pressureless sintering process was performed at 2050 °C for 4 h under a vacuum atmosphere. Microstructural studies revealed that in situ SiC reinforcement was formed and distributed in the composite according to the following reaction: Si + C = SiC. A maximum relative density of 98% was measured for the 20 vol% SiC containing HfB2 composite. Mechanical investigations showed that the hardness and the fracture toughness of these composites were increased and reached up to 21.2 GPa for HfB2-30 vol% SiC and 4.9 MPa.m1/2 for HfB2-20 vol% SiC, respectively. Results showed that alpha-SiC reinforcements were created jagged, irregular, and elongated in shape which were in situ formed between HfB2 grains and filled the porosities. Formation of alpha-SiC contributed to improving the relative density and mechanical properties of the composite samples. By increasing SiC content, an enhanced trend of thermal conductivity was observed as well as a reduced trend for electrical conductivity.

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