scholarly journals Characterization of Irradiation Crosslinked Polyamides for Solar Thermal Applications—Basic Thermo-Analytical and Mechanical Properties

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 969 ◽  
Author(s):  
Patrick Bradler ◽  
Joerg Fischer ◽  
Gernot Wallner ◽  
Reinhold Lang

Polyamide 66 (PA 66) and short glass fiber reinforced versions of PA 66 are widely used for solar-thermal applications, in which thermal and environmental loading of components is from high importance. In this study, the influence of crosslinking via electronic beam irradiation on the morphology and mechanical behavior of unreinforced PA 66 and two types of short glass fiber reinforced PA 66 (30 wt % glass fiber content, 35 wt % glass fiber content) was investigated. In total, five different electronic beam irradiation doses in the range of 0 and 200 kGy were applied. Besides experiments with unconditioned specimens, also preconditioned specimens saturated with water at 80 °C for seven days were investigated. It was found that irradiation causes a shift to lower melting temperatures and lower melting enthalpies, while simultaneously leading to higher glass transition temperatures (TG), increasing small strain modulus values and higher tensile strengths. Also, as expected, preconditioning samples in water at 80 °C to water uptake saturation leads to a shift to lower TG values (‘plasticization’ effect). In terms of tensile behavior at room temperature, water saturated specimens (being above TG at room temperature) exhibited lower modulus and tensile strength values compared to quasi-dry specimens (being below TG at room temperature).

2011 ◽  
Vol 181-182 ◽  
pp. 836-841
Author(s):  
Jiang Liu ◽  
Xiang Guo Liu

Influence of coupling agents on microstructure and mechanical properties of short glass fiber reinforced PA66 composites(SGF/PA66) were investigated by using twin screws extruder and injection machine in this paper. When coupling agents (A1100 or A1100+A+B) were added, short glass fiber was distributed in the PA66 matrix more homogeneously; at the same time, the microstructure and properties of GF/PA66 were improved too. Modified effect of multiple coupling agent (A1100+A+B) is better than that of only A1100 and the desired content of A1100 is about 1.5~2.0wt%. When glass fiber content was less than the critical value (35~40%), mechanical properties of PA composites increase with fiber content increasing, but it begin to decrease when content was excess that value. At last, Failure mechanism of GF/PA66 (treated by A1100 or A1100+A+B) was obtained: adhesion of interface between glass fiber and PA66 matrix, friction after the adhesion, glass fiber pullouted and matrix failure.


Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1569
Author(s):  
Selim Mrzljak ◽  
Alexander Delp ◽  
André Schlink ◽  
Jan-Christoph Zarges ◽  
Daniel Hülsbusch ◽  
...  

Short glass fiber reinforced plastics (SGFRP) offer superior mechanical properties compared to polymers, while still also enabling almost unlimited geometric variations of components at large-scale production. PA6-GF30 represents one of the most used SGFRP for series components, but the impact of injection molding process parameters on the fatigue properties is still insufficiently investigated. In this study, various injection molding parameter configurations were investigated on PA6-GF30. To take the significant frequency dependency into account, tension–tension fatigue tests were performed using multiple amplitude tests, considering surface temperature-adjusted frequency to limit self-heating. The frequency adjustment leads to shorter testing durations as well as up to 20% higher lifetime under fatigue loading. A higher melt temperature and volume flow rate during injection molding lead to an increase of 16% regarding fatigue life. In situ Xray microtomography analysis revealed that this result was attributed to a stronger fiber alignment with larger fiber lengths in the flow direction. Using digital volume correlation, differences of up to 100% in local strain values at the same stress level for different injection molding process parameters were identified. The results prove that the injection molding parameters have a high influence on the fatigue properties and thus offer a large optimization potential, e.g., with regard to the component design.


Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2250
Author(s):  
Mohammad Amjadi ◽  
Ali Fatemi

Short glass fiber-reinforced (SGFR) thermoplastics are used in many industries manufactured by injection molding which is the most common technique for polymeric parts production. Glass fibers are commonly used as the reinforced material with thermoplastics and injection molding. In this paper, a critical plane-based fatigue damage model is proposed for tension–tension or tension–compression fatigue life prediction of SGFR thermoplastics considering fiber orientation and mean stress effects. Temperature and frequency effects were also included by applying the proposed damage model into a general fatigue model. Model predictions are presented and discussed by comparing with the experimental data from the literature.


2011 ◽  
Vol 127 ◽  
pp. 110-114
Author(s):  
Rui Zeng ◽  
Chang Long Du ◽  
Jing Zhao ◽  
Rui Xu

In order to make the switch valve in abrasive-liquid device of premixed abrasive water jet cutting system work normally, the sealing bush which ensures the pressure constant and the switch smooth is needed. The structure, material and craft of the switch valve sealing bush are studied in this paper. The different weight content of short glass fiber reinforced nylon is tested in the environment of no lubricant, water lubricant and oil lubricant. The result shows that in oil lubricant environment, the 33% weight content of short glass fiber reinforced nylon composites have the best capabilities and the least resistance of friction. The experimental result proves that the sealing bush made by the prepared short glass fiber reinforced nylon composites can meet the require of the premixed abrasive water jet cutting system, according to which the sealing bush is producted and assembled to the abrasive-liquid device.


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