Characterisation of an under-cured epoxy adhesive for use on the riv-bonded Bloodhound SSC lower chassis

2015 ◽  
Vol 231 (6) ◽  
pp. 557-567
Author(s):  
Chris J Hannon ◽  
Ben J Evans
Keyword(s):  
Tensile Testing ◽  
Steel Sheet ◽  
Mechanical Analysis ◽  
Epoxy Adhesive ◽  
Significant Loss ◽  
Scanning Calorimetry ◽  
The World ◽  
Cure Temperature ◽  
Cure Pressure ◽  
Large Sections

Bloodhound SSC is a vehicle that aims to raise the World Land Speed Record to over 1000 mile/h in Hakskeen Pan, South Africa. Its lower chassis is a riv-bonded fabrication made using steel sheet for skins and aluminium alloy machinings for bulkheads. Fasteners alone were enough to satisfy the lower chassis structural requirements; however, Redux 312/5 epoxy adhesive was used to increase the stiffness of the structure and limit potential corrosion due to water and soil ingress. The use of dissimilar metals in the chassis could lead to panel buckling during elevated cure temperatures, meaning a low adhesive cure temperature of 80–90 ℃ was required to minimise this risk. As the cure pressure for the lower chassis adhesive was achieved using only rivets, the variation of cure pressure was experimentally investigated and found to be within the manufacturer’s recommendations for large sections of the lower chassis. Tensile testing indicated the chassis could be cured at 80 ℃ instead of the optimum 121 ℃, without significant loss of mechanical strength. A thermal characterisation of the adhesive was conducted using dynamic mechanical analysis and differential scanning calorimetry. A variety of cure profiles was investigated and resulted in a cure profile that maximised the glass transition temperature ( Tg). An increase in cure duration to 8 h was recommended, which resulted in an increase in Tg by 15–24 ℃ to 83–92 ℃.

Novel shape-memory polyurethane fibers for textile applications

2018 ◽  
Vol 89 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Míriam Sáenz-Pérez ◽  
Tariq Bashir ◽  
José Manuel Laza ◽  
Jorge García-Barrasa ◽  
José Luis Vilas ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shape Memory ◽  
Tensile Testing ◽  
Melt Spinning ◽  
Mechanical Analysis ◽  
Knitted Fabric ◽  
Scanning Calorimetry ◽  
Moisture Management ◽  
Potential Applications ◽  
Shape Memory Polyurethane

In this work, thermoresponsive shape-memory polyurethane (SMPU) fibers were produced by melt spinning from different SMPU pellets. Afterwards, the knitted fabric samples were prepared by the obtained fibers. Some of the SMPUs used were synthesized previously in our laboratory whereas a commercial one, named DIAPLEX MM4520, was also evaluated in order to carry out comparative studies. All the SMPUs were characterized by different techniques, such as thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Moreover, the shape-memory capabilities of the fabrics were measured by thermo-mechanical analysis. The obtained results show that the synthesized SMPUs could be attractive candidates for potential applications such as breathable fabrics or moisture-management textiles.

scholarly journals Self-Healing in Mobility-Restricted Conditions Maintaining Mechanical Robustness: Furan–Maleimide Diels–Alder Cycloadditions in Polymer Networks for Ambient Applications

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2543 ◽  
Author(s):  
Dorothee Ehrhardt ◽  
Jessica Mangialetto ◽  
Jolien Bertouille ◽  
Kurt Van Durme ◽  
Bruno Van Mele ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Network Formation ◽  
Polymer Networks ◽  
Mechanical Analysis ◽  
Diels Alder ◽  
Self Healing ◽  
Ambient Conditions ◽  
Scanning Calorimetry ◽  
Diffusion Controlled ◽  
Cure Temperature

Two reversible polymer networks, based on Diels–Alder cycloadditions, are selected to discuss the opportunities of mobility-controlled self-healing in ambient conditions for which information is lacking in literature. The main methods for this study are (modulated temperature) differential scanning calorimetry, microcalorimetry, dynamic rheometry, dynamic mechanical analysis, and kinetic simulations. The reversible network 3M-3F630 is chosen to study the conceptual aspects of diffusion-controlled Diels–Alder reactions from 20 to 65 °C. Network formation by gelation is proven and above 30 °C gelled glasses are formed, while cure below 30 °C gives ungelled glasses. The slow progress of Diels–Alder reactions in mobility-restricted conditions is proven by the further increase of the system’s glass transition temperature by 24 °C beyond the cure temperature of 20 °C. These findings are employed in the reversible network 3M-F375PMA, which is UV-polymerized, starting from a Diels–Alder methacrylate pre-polymer. Self-healing of microcracks in diffusion-controlled conditions is demonstrated at 20 °C. De-gelation measurements show the structural integrity of both networks up to at least 150 °C. Moreover, mechanical robustness in 3M-F375PMA is maintained by the poly(methacrylate) chains to at least 120 °C. The self-healing capacity is simulated in an ambient temperature window between −40 and 85 °C, supporting its applicability as self-healing encapsulant in photovoltaics.

Controlling stereocomplexation, heat resistance and mechanical properties of stereocomplex polylactide films by using mixtures of low and high molecular weight poly(D-lactide)s

e-Polymers ◽  
2018 ◽  
Vol 18 (6) ◽  
pp. 485-490 ◽  
Author(s):  
Yaowalak Srisuwan ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Heat Resistance ◽  
Tensile Properties ◽  
Tensile Testing ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Film Series ◽  
High Molecular Weight Poly

AbstractStereocomplex polylactide (scPLA) films were prepared by blending poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) solutions before solvent evaporation. The PLLA/PDLA ratios were 80/20 and 60/40 (w/w). PDLAs with low and high molecular weights (M.W.) were used as PDLA mixtures. The scPLA films with different low/high M.W. PDLA ratios were investigated for both the 80/20 and 60/40 (w/w) scPLA film series. Stereocomplexation, heat resistance and the mechanical properties of the scPLA films were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and tensile testing, respectively. The results indicated that low M.W. PDLA can enhance the stereocomplexation and heat resistance of scPLA films while the high M.W. PDLA can improve tensile properties of scPLA films. It was concluded that the stereocomplexation, heat resistance and tensile properties of scPLA films could be controlled by adjusting the low/high M.W. PDLA ratio in PDLA fraction.

The Effect of Various Nanoclay Surface Modifications on the Thermal and Mechanical Properties of Amorphous Polyamide Nanocomposites

2020 ◽  
Vol 1010 ◽  
pp. 154-159
Author(s):  
K.A. Abdul Halim ◽  
James E. Kennedy ◽  
Joseph B. Farrell ◽  
Muhammad Salihin Zakaria
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Polymer Nanocomposites ◽  
Polymer Matrix ◽  
Tensile Testing ◽  
Polymer System ◽  
Surface Modifications ◽  
Mechanical Analysis ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry

The addition of nanoclay within polymer matrix is anticipate to enhance the properties of the polymer system. Nonetheless, one of the key elements in property enhancements of a polymer nanocomposites is the surface modifications of the nanoclay. This is due to the affinity between polymer matrix and nanoclay is of important factors should be considered. In this study, amorphous polyamide were melt blended with different nanoclay grades with different surface modifications in order to evaluate the best clay grade for the polymer system. The thermal analysis carried out on the amorphous polyamide nanocomposites were carried out by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) whereas the mechanical properties were investigated using tensile testing. It was observed that there were changes in the glass transition temperature (Tg) of the nanocomposites due to clay additions. Further, the storage modulus was found to increase as a result of nanoclay incorporation. The type of clay grades significantly affects the mechanical properties of the amorphous polyamide nanocomposites.

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.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

scholarly journals Relationship between the Stereocomplex Crystallization Behavior and Mechanical Properties of PLLA/PDLA Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1851
Author(s):  
Hye-Seon Park ◽  
Chang-Kook Hong
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Behavior ◽  
Mechanical Analysis ◽  
X Ray Diffraction ◽  
Nucleation Agent ◽  
Scanning Calorimetry ◽  
Nucleation Sites ◽  
Wide Range ◽  
Degree Of Crystallization

Poly (l-lactic acid) (PLLA) is a promising biomedical polymer material with a wide range of applications. The diverse enantiomeric forms of PLLA provide great opportunities for thermal and mechanical enhancement through stereocomplex formation. The addition of poly (d-lactic acid) (PDLA) as a nucleation agent and the formation of stereocomplex crystallization (SC) have been proven to be an effective method to improve the crystallization and mechanical properties of the PLLA. In this study, PLLA was blended with different amounts of PDLA through a melt blending process and their properties were calculated. The effect of the PDLA on the crystallization behavior, thermal, and mechanical properties of PLLA were investigated systematically by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), polarized optical microscopy (POM), dynamic mechanical analysis (DMA), and tensile test. Based on our findings, SC formed easily when PDLA content was increased, and acts as nucleation sites. Both SC and homo crystals (HC) were observed in the PLLA/PDLA blends. As the content of PDLA increased, the degree of crystallization increased, and the mechanical strength also increased.

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.

scholarly journals Combined thermal analysis of plant oils

2021 ◽  
Author(s):  
Kinga Tamási ◽  
Kálmán Marossy
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Low Temperature ◽  
Glassy State ◽  
Mechanical Analysis ◽  
Plant Oils ◽  
Scanning Calorimetry ◽  
Natural Plant ◽  
The Moment ◽  
Current Reversal

AbstractThe paper deals with the study of seven selected natural plant oils. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermally stimulated discharge (TSD) methods were used. It has been found that most of the oils tested are in a glassy state at low temperature and have multiple transitions in the low temperature range. DSC shows complex melting-like processes or glass transition. For both DMA and TSD, the scaffold supportive method was used and found as a suitable one. DMA and TSD proved more sensitive than DSC and revealed at least two transitions between − 120 and − 40 °C. In the case of three oils (argan, avocado and sunflower), current reversal was observed by TSD; this symptom cannot be fully explained at the moment.

scholarly journals Effects of Ni Additions on the High Temperature Expansion, Melting and Oxidation Behaviors of Cobalt-Based Superalloys

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Patrice Berthod ◽  
Lionel Aranda ◽  
Jean-Paul Gomis
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Beneficial Effects ◽  
Ni Addition ◽  
High Temperature Expansion ◽  
High Fraction ◽  
Thermal Analysis Techniques ◽  
Ni Additions

Nickel is often added to cobalt-based superalloys to stabilize their austenitic structure. In this work the effects of Ni on several high temperature properties of a chromium-rich cobalt-based alloy reinforced by high fraction of TaC carbides are investigated. Different thermal analysis techniques are used: differential scanning calorimetry (DSC), thermo-mechanical analysis (TMA) and thermogravimetry (TG). Results show that the progressive addition of nickel did not induce great modifications of microstructure, refractoriness or thermal expansion. However, minor beneficial effects were noted, including reduction of the melting temperature range and slight decrease in thermal expansion coefficient. The most important improvement induced by Ni addition concerns the hot oxidation behavior. In this way, introducing several tens wt % Ni in this type of cobalt-based alloy may be recommended.

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