The Effect of Masked Isocyanates on the Mechanical Properties of My720/dds Epoxy Resin

1989 ◽  
Vol 171 ◽  
Author(s):  
N. Rungsimuntakul ◽  
S.V. Lonikar ◽  
R. E. Fornes ◽  
R.D. Gilbert
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Epoxy Resins ◽  
Moisture Absorption ◽  
Peak Stress ◽  
Fiber Composites ◽  
Elongation At Break ◽  
Initial Modulus ◽  
Better Than

ABSTRACTThe mechanical properties of epoxy resins and epoxy resin/graphite fiber composites are adversely affected by moisture absorption. Incorporation of masked isocyanates that unmask to release isocyanates in situ at the cure temperatures (150-177ºC) reduce the equilibrium absorption up to ∼70%. Dynamic mechanical analyses and stress-strain properties of epoxy resins containing masked isocyanates were examined to determine their effect on mechanical properties. The ultimate Tg of the epoxy is reduced by incorporation of masked isocyanate, but the actual Tg is comparable to the “as cured” Tg of the epoxy. The dynamic moduli up to the Tg are relatively unaffected. Ina number of cases, the initial modulus, elongation at break and peak stress are equal or better than the unmodified resins.

scholarly journals Analysis of Mechanical and Wettability Properties of Natural Fiber-Reinforced Epoxy Hybrid Composites

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2827
Author(s):  
Ayyappa Atmakuri ◽  
Arvydas Palevicius ◽  
Madhusudan Siddabathula ◽  
Andrius Vilkauskas ◽  
Giedrius Janusas
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Epoxy Resin ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Matrix Material ◽  
Research Work ◽  
Fiber Composites ◽  
Individual Fiber

Natural fibers have many advantages over synthetic fibers due to their lightness, low cost, biodegradability, and abundance in nature. The demand for natural fiber hybrid composites in various applications has increased recently, because of its promising mechanical properties. In this research work, the mechanical and wettability properties of reinforced natural fiber epoxy resin hybrid composites were investigated. The main aim of this research work is the fabrication of hybrid composites and exploit its importance over individual fiber composites. The composites were fabricated based on the rule of hybridization mixture (0.4 wf) of two fibers using sets of either hemp and flax or banana and pineapple, each set with 40 wt%, as well as four single fiber composites, 40 wt% each, as reinforcement and epoxy resin as matrix material. A total of two sets (hemp/flax and banana/pineapple) of hybrid composites were fabricated by using a hand layup technique. One set as 40H/0F, 25H/15F, 20H/20F, 15H/25F, 0H/40F, and the second one as 40B/0P, 25B/15P, 20B/20P, 15B/25P, 0B/40P weight fraction ratios. The fabricated composites were allowed for testing to examine its mechanical, wettability, and moisture properties. It has been observed that, in both cases, hybrid composites showed improved mechanical properties when compared to the individual fiber composites. The wettability test was carried out by using the contact angle measurement technique. All composites in both cases, hybrid or single showed contact angle less than 90°, which is associated with the composite hydrophilic surface properties. The moisture analysis stated that all the composites responded for moisture absorption up to 96 h and then remained constant in both cases. Hybrid composites absorbed less moisture than individual fiber composites.

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

Test Methods for Mechanical Properties of Structural Adhesives

2010 ◽  
Vol 97-101 ◽  
pp. 814-817 ◽  
Author(s):  
Jun Deng
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Shear Strength ◽  
Elastic Modulus ◽  
Butt Joint ◽  
Test Methods ◽  
Joint Specimen ◽  
Lap Shear ◽  
Better Than

One of the greatest drawbacks to predicting the behaviour of bonded joints has been the lack of reliable data on the mechanical properties of adhesives. In this study, methods for determining mechanical properties of structural adhesive were discussed. The Young’s modulus, Poisson’s ratio and tensile strength of the adhesive were tested by dogbone specimens (bulk form) and butt joint specimens (in situ form). The shear modulus and shear strength were test by V-notched specimens (bulk form) and thick adherend lap-shear (TALS) joint specimens (in situ form). The test results show that the elastic modulus provided by the manufacturer is too low, the dogbone specimen is better than the butt joint specimen to test the tensile strength and elastic modulus and the TALS joint specimen is better than the V-notched specimen to test the shear strength.

scholarly journals A Study Regarding the Mechanical Properties of a Hybrid Matrix with Various Volume Proportions of Dammar

2020 ◽  
Vol 57 (1) ◽  
pp. 133-140
Author(s):  
Dumitru Bolcu ◽  
Marius Marinel Stanescu ◽  
Ion Ciuca ◽  
Cosmin Mihai Miritoiu ◽  
Alin Dinita ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Vibration Mode ◽  
Vibration Damping ◽  
The Other ◽  
Damping Properties ◽  
Elongation At Break ◽  
Hybrid Resin ◽  
Natural Resin ◽  
Volume Proportion

This paper studies the influence of the volume proportion between components on the mechanical behaviour of a hybrid resin obtained by combining the natural resin Dammar and epoxy resin. We analyse three sets of hybrid resin samples, in which we used a Dammar volume proportion of 60%, 70%, and 80% respectively and epoxy resin (employed together with its associated reinforcement in order to generate a quick process of polymerization). Following the tensile test we found the characteristic curves, the tensile strength and the elongation at break for each of the three types of resins. We also looked into the vibration damping properties of bars made of this resin. We experimentally determined the frequency and the damping coefficient of the first particular vibration mode for one bar taken out of each set of resins, with one end fixed and the other free. On the basis of the results, we calculated the loss coefficient for each type of resin.

scholarly journals Influence of Furfuryl Alcohol Fiber Pre-Treatment on the Moisture Absorption and Mechanical Properties of Flax Fiber Composites

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 59 ◽  
Author(s):  
Yunlong Jia ◽  
Bodo Fiedler
Keyword(s):  
Mechanical Properties ◽  
Furfuryl Alcohol ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Tensile Tests ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Moisture Resistance ◽  
Structural Applications ◽  
Pre Treatment

Poor moisture resistance of natural fiber reinforced bio-composites is a major concern in structural applications. Many efforts have been devoted to alleviate degradation of bio-composites caused by moisture absorption. Among them, fiber pre-treatment has been proven to be effective. This paper proposes an alternative “green” fiber pretreatment with furfuryl alcohol. Pre-treatments with different parameters were performed and the influence on the mechanical properties of fiber bundles and composites was investigated. Moisture resistance of composites was evaluated by water absorption tests. Mechanical properties of composites with different water contents were analyzed in tensile tests. The results show that furfuryl alcohol pretreatment is a promising method to improve moisture resistance and mechanical properties (e.g., Young’s modulus increases up to 18%) of flax fiber composites.

Thermo Mechanical behaviour of Phenol Novolac Resin and Unsaturated Polyester Toughened Epoxy using nano Bentonite and Silica Nanoparticles

2020 ◽  
Vol 1 (3) ◽  
pp. 77-83
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Silica Nanoparticles ◽  
Moisture Absorption ◽  
Unsaturated Polyester ◽  
Physical And Mechanical Properties ◽  
Bending Test ◽  
Mechanical And Thermal Properties ◽  
Novolac Epoxy ◽  
Industrial Needs

Phenol novolac epoxy resin is a polymer matter which its properties can be modified for industrial needs. In this research, nanocomposites of phenol novolac epoxy resin and unsaturated polyester are made nano Bentonite and silica nanoparticles as filler. For this purpose, effect of nanoparticles percent on nanocomposite formation is studied and their physical, mechanical and thermal properties are obtained. The presence of unsaturated polyester in this process forms a cross-link capable of improving the physical and mechanical properties of epoxy resin. Fracture behavior was determined by a SEM device. Moreover, TGA, DSC, impact tests and bending test were applied for data analysis. When process ability is growing, moisture absorption decreases. Fracture toughness was also evaluated in a stoichiometric network. Physical and mechanical properties improve significantly with increasing nanoparticles. The most important reason for using this nanocomposite is its high resistance to corrosion.

Correlation between Curing Temperature and the Properties of Conductive Composites

2013 ◽  
Vol 750-752 ◽  
pp. 119-122 ◽  
Author(s):  
Xiao Ya Wang ◽  
Zhi Dong Xia ◽  
Zhe Li
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Crosslink Density ◽  
Fracture Morphology ◽  
Curing Temperature ◽  
Tensile Fracture ◽  
Elongation At Break ◽  
Conductive Composites ◽  
The Stability ◽  
Better Than

This study was carried out to discuss the influence of curing temperature on the performance of conductive composites filled with nickel-coated graphite (NCG). The electrical conductivity, crosslink density, mechanical properties and tensile fracture morphology have been investigated. The results indicated that curing temperature had great impact on the electrical conductivity and mechanical properties. Voluem resistivity decreased from 43.1 to 0.08 ohm-cm at 125°C-205°C, and the reason was discussed in light of formation and break of the conductive network in the composites. The stability of SR-NCG cured at 165°C-205°C were also better than those cured at other curing temperature. Besides, tensile strength increased from 2.41 to 7.19Mpa at 125°C-225°C, elongation at break have a 56% increase, and Shore A hardness also incresed from 74 to 82.

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