Melt-recrystallization of poly (L-lactic acid) initially containing α′-crystals

Publication date: Available online 23 May 2019Source: PolymerAuthor(s): René Androsch, Rui Zhang, Christoph SchickAbstractThe kinetics of melt-recrystallization and the stability of crystal self-nuclei of poly (l-lactic acid) initially containing disordered α′-crystals with a melting temperature of around 150 °C has been analyzed using specifically designed fast scanning chip calorimetry experiments (FSC). In general, the rate of recrystallization of the melt after complete melting of α′-crystals decreases with increasing melt-temperature mainly due to the lowering of the self-nuclei concentration. Self-nuclei of highest stability survive up to about 170 °C. The concentration of self-nuclei/α′-crystal remnants at a specific melt-temperature between 150 and 170 °C is independent on time, that is, only the temperature of the melt controls the self-nuclei content. Combining fast scanning calorimetry with polarized-light optical microscopy and with atomic force microscopy allows studying the semicrystalline morphology of samples of different self-nucleation history, providing direct information about the self-nuclei concentration in the various melts.Graphical abstract
Source: Polymer - Category: Chemistry Source Type: research

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Publication date: Available online 16 June 2019Source: Journal of Hazardous MaterialsAuthor(s): Lingjun Kong, Yang Ruan, Qingying Zheng, Minhua Su, Zenghui Diao, Diyun Chen, Li’an Hou, Xiangyang Chang, Kaimin ShihAbstractA considerable amount of uranium (U(VI))-containing industrial wastewater is generated from both uranium mining and processing, and nuclear electrical power generation. Discharge of U(VI) containing wastewater causes severe damage to the environment and leads to a loss of resources. Uranium sorption on hydroxyapatite (HAP) has been studied extensively to address the abovementioned issues. In the pres...
Source: Journal of Hazardous Materials - Category: Environmental Health Source Type: research
In this study, we used nano-smectite (SMT) and multiwall carbon nanotube (MWCNT) as a recognition surface over the disposable pencil graphite electrode for the low-level detection of ascorbic acid (AA) and acetyl salicylic acid (ACA). Firstly, nano-semectit was obtained by the purification of natural bentonite clay. XRD patterns and Scanning electron microscopy (SEM) were employed to ensure the purity of the bentonite samples. Pencil graphite rodes were immersed into suspensions of SMT, MWCNT or the both.The surface morphology of the sensor was investigated by cyclic voltammery (CV), electrochemical impedance spectroscopy ...
Source: Talanta - Category: Chemistry Authors: Tags: Talanta Source Type: research
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Source: Talanta - Category: Chemistry Authors: Tags: Talanta Source Type: research
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Source: International Journal of Surgery Case Reports - Category: Surgery Source Type: research
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Source: International Journal of Surgery Case Reports - Category: Surgery Source Type: research
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Source: Cardiovascular Intervention and Therapeutics - Category: Cardiology Source Type: research
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Source: Current Neurology and Neuroscience Reports - Category: Neuroscience Source Type: research
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Source: European Journal of Radiology - Category: Radiology Source Type: research
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Source: WBZ-TV - Breaking News, Weather and Sports for Boston, Worcester and New Hampshire - Category: Consumer Health News Authors: Tags: Health News Offbeat CNN Facebook Source Type: news
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Source: ClinicalTrials.gov - Category: Research Source Type: clinical trials
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