scholarly journals Compatibilization and Toughening of Biodegradable Poly (Lactic Acid) / Cellulose Acetate Films by Polyamide Amine Dendrimers

Author(s):  
Yansong Huang ◽  
Yu juan Jin ◽  
Bo Wang ◽  
Huafeng Tian ◽  
Yunxuan Weng ◽  
...  

Abstract Due to the poor compatibility caused by the large difference in hydrophilicity and interface between polylactic acid (PLA) and cellulose acetate (CA), the blending of the two materials is difficult and the application is limited. To solve this problem, a type of polyamide amine (PAMAM) dendrimer was introduced to modify PLA / CA blends in this work. The results showed that PAMAM could improve the compatibility of PLA / CA blends, promote the distribution of CA and crystallization of PLA. At the same time, adding PAMAM could enhance the mechanical properties of the blend material, and the toughness and tear strength were increased by 551% and 141%, respectively. In addition, the incorporation of PAMAM increased hydrophobicity and oxygen permeability of PLA/ CA blends, and the oxygen permeability could be increased by up to 3 orders of magnitude. Degradation test results showed that the blend exhibited good biodegradability. The overall performance of the PLA/ CA blend film was optimal when the content of PAMAM was 3 phr. The biodegradable blend films with excellent performance provided wide application prospect in the food green packaging fields.

LWT ◽  
2021 ◽  
pp. 112356
Author(s):  
Phatthranit Klinmalai ◽  
Atcharawan Srisa ◽  
Yeyen Laorenza ◽  
Wattinee Katekhong ◽  
Nathdanai Harnkarnsujarit

Author(s):  
Nilay Tuccar Kilic ◽  
Buse Nur Can ◽  
Mehmet Kodal ◽  
Güralp Özkoç

In this study, the compatibilization effects of triglycidylisobutyl polyhedral oligomeric silsesquioxane (TEpPOSS) on biodegradable poly(lactic acid) (PLA)/thermoplastic polyurethane (TPU) blends were investigated. All blends were prepared via melt blending and PLA/TPU (80/20, 70/30, 50/50 wt%) ratio was selected as the experimental parameter. In order to predict the selective localization of TEpPOSS thermodynamically, wetting coefficient were determined by means of surface energy measurements. Morphological analyses were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Moreover, rheological, mechanical, thermomechanical and thermal properties of the blends were performed via rheometer, universal tensile tester, dynamic mechanic analyses and differential scanning calorimeter (DSC), respectively. Morphological test results revealed that TEpPOSSs were mostly located at the interfaces of the PLA and TPU phases. According to the rheological studies, the interfacial interactions between PLA and TPU were improved with the addition of TEpPOSS, which resulted from the potential reactions between epoxy-carboxylic acid and/or epoxy-hydroxyl functional groups. The addition of TEpPOSS enhanced the mechanical properties of PLA/TPU blends. DSC test results revealed a decrease in the glass transition temperatures of PLA in the presence of TEpPOSS, which was an another indication of improved compatibility between PLA and TPU.


e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 234-243
Author(s):  
Yue Ding ◽  
Cai Zhang ◽  
Congcong Luo ◽  
Ying Chen ◽  
Yingmei Zhou ◽  
...  

Abstract Biodegradable nanocomposites were prepared by melt blending biodegradable poly(lactic acid) (PLA) and poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30, w/w) with diatomite or talc (1–7%). From the SEM test, the particles were transported to the interface of two phases, which acted as an interface modifier to strengthen the interfacial adhesion between PLA and PBAT. Talc and diatomite acted as nucleating agents to improve the crystallization of PBAT in the blends by DSC analysis. Moreover, adding the particles improved the tensile and impact toughness of the blends. The elongation at break with 5% talc was 78% (vs ∼21%) and the impact strength was 15 kJ/m2 (vs ∼6.5 kJ/m2). The rheological measurement revealed that the talc and diatomite reduced the viscosity of the blends. The results showed a good possibility of using talc- and diatomite-filled PLA/PBAT blends with high toughness for green-packaging and bio-membranes application.


2018 ◽  
Vol 381 (1) ◽  
pp. 1800133 ◽  
Author(s):  
Elaine C. Lopes Pereira ◽  
Bluma G. Soares ◽  
Rayan B. Jesus ◽  
Alex S. Sirqueira

Author(s):  
Romney Humphries ◽  
Shelley Campeau ◽  
Thomas E. Davis ◽  
Kristin J. Nagaro ◽  
Vincent J. LaBombardi ◽  
...  

In this multisite study, VITEK® 2 AST-Gram-Negative Ceftazidime-Avibactam (CZA) test results for 1073 isolates (866 Enterobacterales and 207 Pseudomonas aeruginosa) were compared to the Clinical & Laboratory Standards Institute (CLSI) broth microdilution (BMD) reference method. The results were analyzed for essential agreement (EA), category agreement (CA), major error rates, and very major error rates following FDA/ISO performance criteria using the FDA-recognized CLSI/EUCAST breakpoints (S ≤8/4 μg/ml and R ≥16/4 μg/ml). The overall EA was 94.5% (1014/1073) and CA was 98.7% (1059/1073). No very major errors were reported. The major error rate was 1.4% (14/998). Out of 14 major errors, 9 were within EA. Based on the EA and lack of an intermediate category for CZA, the adjusted major error rate for FDA criteria was 0.5% (5/998). The performance for ISO criteria after error resolutions included EA 94.5% (1014/1073), CA 98.9% (1061/1073), major error 1.2% (12/998), and no very major error. Vitek 2 met the ISO and FDA criteria of ≥95% reproducibility and ≥95% quality control (QC) results within acceptable ranges for QC organisms. Vitek 2 overall performance for Enterobacterales and P. aeruginosa met or exceeded the FDA and ISO performance criteria and thus is a reliable alternative to BMD reference method for routine CZA susceptibility testing.


2015 ◽  
Vol 7 (1) ◽  
pp. 59 ◽  
Author(s):  
Solange Muglia Wechsler ◽  
Tatiana De Cassia Nakano ◽  
Simone Ferreira da Silva Domingues ◽  
Helena Rinaldi Rosa ◽  
Roselaine Berenice Ferreira da Silva ◽  
...  

This study aimed to determine whether performance on tests of crystallized intelligence is affected by gender and to ascertain whether differential item parameters could account for the gender disparities. The sample comprised 1.191 individuals (55% women) between the ages of 16 and 77 years old (M=22; SD=9.5). The participants were primarily college students (58.3%) living in four Brazilian states. Four verbal tests measuring crystallized intelligence (vocabulary, synonyms, antonyms and verbal analogies) were constructed and administered in a group setting. An analysis of variance revealed no significant differences in the overall performance between men and women. However, a differential item functioning analysis indicated significant differences on 8.7% of the items, which indicates the existence of gender bias. Because bias can limit women’s access to social opportunities, the results obtained indicate the importance of reducing item bias in cognitive measures to ensure the accuracy of test results.


2021 ◽  
pp. 096739112110576
Author(s):  
Ying Zhou ◽  
Can Chen ◽  
Lan Xie ◽  
Xiaolang Chen ◽  
Guangqiang Xiao ◽  
...  

In this work, novel plasticizing biodegradable poly (lactic acid) (PLA) composites were prepared by melt blending of jute and tung oil anhydride (TOA), and the physical and mechanical properties of PLA/jute/TOA composites were tested and characterized. The impact strength of PLA/jute/TOA composites significantly increases with increasing the content of TOA. The SEM images of fracture surface of PLA/jute/TOA composites become rough after the incorporation of TOA. In addition, TOA changes the crystallization temperature and decomposition process of PLA/jute/TOA composites. With increasing the amount of TOA, the value of storage modulus (E′) of PLA/jute/TOA composites gradually increases. The complex viscosity (η*) values for all samples reduce obviously with increasing the frequency, which means that the pure PLA and PLA/jute/TOA composites is typical pseudoplastic fluid. This is attributed to the formation of crosslinking, which restricts the deformation of the composites.


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