The preparation of polyamide 11 composites with extremely long ignition time

Author(s):  
Xiaodong Jin ◽  
Suping Cui ◽  
Shibing Sun ◽  
Jun Sun ◽  
Sheng Zhang ◽  
...  
Keyword(s):  
Author(s):  
Dyah Marganingrum ◽  
Lenny Marilyn Estiaty

Aim: This paper aims to explain the added value increasing method of reject coal which has not utilized by the company. Methodology and Results: The method to increase added value in this study used the agglomeration process of briquettes form that changing composition by adding biomass. The biomass functions to minimize bottom ash produced from burning briquettes so that the briquettes burn entirely. Stages processes in this study consist of characterization, briquetting, physical test, and chemical test. Based on the analysis, reject coal still has a high calorific value of 5,929 cal/gr. Shapes and sizes that were not following needs of coal market or consumer due to reject coal to be a waste. Briquettes have been successfully produced and meet specification requirements based on applicable regulations in Indonesia. Besides physical properties, the briquette meet density requirements which are greater than or equal to 1 gr/cm3 and shatter index value is less than 0.5%. The gas emission test shows below threshold, which is CO 0-30 ppm, H2S 0-3.6 ppm, and NOx is not detected. After evaluation, it showed that by adding 30% biomass, ignition time could be decreased and remaining unburned briquettes or bottom ash was reduced as much as 68.68%. Conclusion, significance and impact study: The bio-coal briquettes is a strategic solution to environmental problems and alternative energy sources that are environmentally friendly, because CO and H2S emissions are still below the threshold, even for NOx not detected. Making Bio-coal briquettes as a solution to the utilization of reject coal mining waste to be used as an alternative energy source has been successfully carried out.


2021 ◽  
pp. 089270572110133
Author(s):  
Ayrton Alef Castanheira Pereira ◽  
José Roberto Moraes d’Almeida

Besides polyamide 11 (PA 11) outstanding properties, wear performance is considered a key factor for its continued widespread use. TiTanate NanoTubes (TTNT) have a huge potential as reinforcement in polymer matrix nanocomposites, and although nanotubes reinforcement capacity is well understood, its effect on tribological characteristics is still an open question. Thus, the present work has as objective to study the wear behavior of PA 11 and its nanocomposites, highlighting TTNT loading, functionalization and sodium content effects. Seeking the possibility to tailor properties, surface topography is investigated. Based on parameter classification, correlation and functional sense, an ideal roughness parameter set is defined. By taking measurements in X- and Y-axis, parameter variations and sensibility are also analyzed. From the results, maximum wear resistance can be reached in functionalized samples with low TTNT loading and high sodium content. Some roughness parameters demonstrate a moderate to strong correlation with wear performance. Parameter variations are mainly attributed to the non-stationarity of the surface.


Author(s):  
Zahid Iqbal Khan ◽  
Zurina Binti Mohamad ◽  
Abdul Razak Bin Rahmat ◽  
Unsia Habib ◽  
Nur Amira Sahirah Binti Abdullah

This work explores a novel blend of recycled polyethylene terephthalate/polyamide 11 (rPET/PA11). The blend of rPET/PA11 was introduced to enhance the mechanical properties of rPET at various ratios. The work’s main advantage was to utilize rPET in thermoplastic form for various applications. Three different ratios, i.e. 10, 20 and 30 wt.% of PA11 blend samples, were prepared using a twin-screw extruder and injection moulding machine. The mechanical properties were examined in terms of tensile, flexural and impact strength. The tensile strength of rPET was improved more than 50%, while the increase in tensile strain was observed 42.5% with the addition of 20 wt.% of PA11. The improved properties of the blend were also confirmed by the flexural strength of the blends. The flexural strength was increased from 27.9 MPa to 48 MPa with the addition of 30 wt.% PA11. The flexural strain of rPET was found to be 1.1%. However, with the addition of 10, 20 and 30 wt.% of PA11, the flexural strain was noticed as 1.7, 2.1, and 3.9% respectively. The impact strength of rPET/PA11 at 20 wt.% PA11 was upsurged from 110.53 to 147.12 J/m. Scanning electron microscopy analysis revealed a dispersed PA11 domain in a continuous rPET matrix morphology of the blends. This work practical implication would lead to utilization of rPET in automobile, packaging, and various industries.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2139
Author(s):  
Wei Shian Tey ◽  
Chao Cai ◽  
Kun Zhou

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.


2016 ◽  
Vol 93 ◽  
pp. 153-162 ◽  
Author(s):  
Lidija Mancic ◽  
Patricia I. Pontón ◽  
Sonia Letichevsky ◽  
Antonio M. Costa ◽  
Bojan A. Marinkovic ◽  
...  

2012 ◽  
Vol 110 (1) ◽  
pp. 485-487 ◽  
Author(s):  
Jozef Martinka ◽  
Karol Balog ◽  
Tomáš Chrebet ◽  
Emília Hroncová ◽  
Janka Dibdiaková

Author(s):  
A.M. Sverchkov ◽  

It is proposed to use the new approach to assessing quantitative risk indicators. This approach allows to consider the temporal non-stationarity of the number of processes, including the development of an accident and the spatial movements of people. The greatest uncertainty in the risk analysis with an explosive and fire hazard component is not the frequency of initiating events used, but, for example, data on the probability of ignition. The range of variation of this probability is about two orders of magnitude (relatively speaking, from 1 % to 100 %), and the criteria and factors that determine the choice of this value are not always clearly defined. The paper proposes an approach that considers the probability of ignition as a dependence on the time that passed after the start of emergency depressurization. Knowing this dependence, it is possible to consider several scenarios with different ignition time after the start of the release and assign certain consequences and probabilities to each scenario. Moreover, it is possible for each single scenario on a specific piece of equipment (pipeline section) to obtain non-stationary, namely time-varying potential risk fields. The example of an accident on the oil pipeline is considered, the risk indicators of such an accident are calculated, it is shown that the risks can change over time, namely they are non-stationary characteristics. Further, this fact is transformed into the development of theoretical foundations for quantitative risk assessment, considering the non-stationarity of various processes occurring during emergency situations arising during the operation of equipment, individual behavior of people and changes in external conditions. The results obtained show the importance of considering the changes that occur during an emergency on the main oil and product pipelines. It is concluded that the proposed approach allows to reduce the conservatism of assessments provided by traditional methods. In real practice this approach can reasonably reduce the risk indicators by several times, sometimes by orders of magnitude.


2018 ◽  
Vol 89 (15) ◽  
pp. 3189-3200 ◽  
Author(s):  
Yunji Gao ◽  
Guoqing Zhu ◽  
Hui Zhu ◽  
Weiguang An ◽  
Yu Xia

In this paper, moisture content effects on horizontal flame spread were experimentally investigated using 0.245 mm thick, 28 cm tall and 28 cm wide untreated cotton fabric sheets with various moisture contents varying from 0 to 34%. The pyrolysis spread rates, flame heights and ignition times were obtained and analyzed. The corresponding results are as follows: as moisture content increases, the flame height and spread rate first increase and then decrease. In contrast, the ignition time shows an opposite trend with moisture content. The extreme values are observed in cases of 2% moisture content samples. Moreover, the flame spread rate in the warp direction is larger than that in the weft direction. For horizontal flame spread, the moisture content has the effect of consuming part of the heat feedback, which can play a role in reducing the flame spread rate; simultaneously, the moisture content can enlarge flame size and increase the convective heat transfer coefficient, thereby resulting in an increase in flame spread rate. The non-monotonous trend in pyrolysis spread rate is the result of competition between these effects.


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