The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends

[EN] In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30 wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6 phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10 °C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.This research was supported by the Ministry of Economy and Competitiveness-MINECO, Ref: MAT2014-59242-C2-1-R. Authors also thank to "Conselleria d'Educacio, Cultura i Esport"-Generalitat Valenciana, Ref: GV/2014/008 for financial support.Ferri Azor, JM.; García García, D.; Sánchez Nacher, L.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2016). The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends. Carbohydrate Polymers. 147:60-68. https://doi.org/10.1016/j.carbpol.2016.03.082S606814

Radar Reflectivity Derived Rain-storm Characteristics over Northern Thailand

The radar data analysis in this study were to extract the radar reflectivity to individual rain-storms and present the study on rain-storm characteristics with their crucial features in northern Thailand over 80 days between April and August 2012. This study classified the two seasonal variations of rain-storm characteristics derived from Thunderstorm Identification and Tracking Analysis and Nowcasting (TITAN) algorithm including 11 variables of storm numbers, duration, volume, mass, sizes, maximum reflectivity and movement in the data set. Additionally, the study also evaluated statistically the relationship between storm characteristics and standard instability indices including lift index (LI) and convective available potential energy (CAPE). It can be seen that in summer season had a smaller number of storms but the storms were of longer average duration, greater maximum reflectivity as well as larger areas, volume and mass. Most rain-storms in both summer and rainy seasons were less than 2 hours and the storm altitudes (base to top height) were between around 2 and 8 km MSL. The storm velocity was not exceeding 20 km/hr and their movement was southeasterly wind accordingly along the north-south mountain ranges in northern Thailand. Storm area was the most important factor determining the convective weather in the large scale environment during summer season since it was illustrated the strongest correlation in both LI (negative; -0.67) and CAPE (positive; 0.65). Alternatively, the storm duration was the most important variable in wet season, which was exhibited the strongest correlation (0.68) with CAPE as well; moreover, no such strong correlation was found for LI

Characteristics of Hailstorm over Northern Thailand during Summer Season

This study focused on the potential parameters, as a result of the upper-air sounding with radiosonde and of the dual polarization radar for detecting hailstorms. The data were collected during the 2012 summer consisting of 12 hail and 1129 no-hail rainstorms of seven studied dates from April to May, 2012. They were analyzed to discern the character of hail and use them as data for detecting hail echoes and for severe weather forecast in upper Thailand. On the day of hail, the instability indices were high enough to contribute to its formation. The following indices include Lifted Index (LI), Showalter Index (SI) and Convective Available Potential Energy (CAPE). LI and SI displayed the marginally instability ranged -1 to -4. In the case of CAPE, it could reach the extreme instability (CAPE > 2500 J/kg) and also came with the large updraft speed. TITAN software (Thunderstorm Identification, Tracking, Analysis and Nowcasting) was also applied for comparing rainstorms with hailstorms. The significant seven echo characteristics included storm period, speed, mean-maximum reflectivity in the horizontal polarization (ZH), area, volume and mass. Based on the character and frequency distributions in summer, hailstorms had greater values of storm duration, area, volume, mass, speed and highest reflectivity than individual rainstorms. Besides, the mean reflectivity of the storms was a negligible factor to identify the type of storm.For the case study on hail by determining polarimetric radar measurement at S-band across Chiang Maun, Northern Thailand, radar signatures with EDGE software showed that the hail was detected 100% during its falling. It also presented as followings: Vertically integrated liquid (VIL) exceeding 100 kg/m2, ZH over 60dBZ near the surface and ETOP greater than 17 km. Differential reflectivity (ZDR) of rain-hail mixtures almost reached zero. In addition, the coincidental values of correlation coefficient (CC) were ranged 0.988 and 0.996, and specific differential phase (KDP) was ranged 2.1 and 3.2 deg/km

Improving the toughening in poly(lactic acid)-thermoplastic cassava starch reactive blends

Poly(lactic acid) (PLA), a physical blend of PLA and thermoplastic cassava starch (TPCS) (PLA-TPCS), and reactive blends of PLA with TPCS using maleic anhydride as compatibilizer with two different peroxide initiators [i.e., 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (L101) and dicumyl peroxide (DCP)] PLA-g-TPCS-L101 and PLA-g-TPCS-DCP were produced and characterized. Blends were produced using either a mixer unit or twin-screw extruder. Films for testing were produced by compression molding and cast film extrusion. Morphological, mechanical, thermomechanical, thermal, and optical properties of the samples were assessed. Blends produced with the twin-screw extruder resulted in a better grade of mixing than blends produced with the mixer. Reactive compatibilization improved the interfacial adhesion of PLA and TPCS. Scanning electron microscopy images of the physical blend showed larger TPCS domains in the PLA matrix due to poor compatibilization. However, reactive blends revealed smaller TPCS domains and better interfacial adhesion of TPCS to the PLA matrix when DCP was used as initiator. Reactive blends exhibited high values for elongation at break without an improvement in tensile strength. PLA-g-TPCS-DCP provides promising properties as a tougher biodegradable film.Fil: Bher, Anibal Ricardo. Michigan State University; Estados Unidos. Universidad Nacional de San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Auras, Rafael. Michigan State University; Estados UnidosFil: Schvezov, Carlos Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentin