scholarly journals Fully Biodegradable Poly(lactic acid)/Poly(propylene carbonate) Shape Memory Materials with Low Recovery Temperature Based on in situ Compatibilization by Dicumyl Peroxide

2018 ◽  
Vol 36 (6) ◽  
pp. 783-790 ◽  
Author(s):  
Sheng-Xue Qin ◽  
Cui-Xiang Yu ◽  
Xue-Yang Chen ◽  
Hai-Ping Zhou ◽  
Li-Fen Zhao
Keyword(s):  
Lactic Acid ◽  
Shape Memory ◽  
Poly Lactic Acid ◽  
Dicumyl Peroxide ◽  
In Situ Compatibilization ◽  
Biodegradable Poly ◽  
Shape Memory Materials ◽  
Poly Propylene ◽  
Recovery Temperature

scholarly journals Morphology, Thermal, Mechanical Properties and Rheological Behavior of Biodegradable Poly(butylene succinate)/poly(lactic acid) In-Situ Submicrofibrillar Composites

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2422 ◽  
Author(s):  
Zhiwen Zhu ◽  
Hezhi He ◽  
Bin Xue ◽  
Zhiming Zhan ◽  
Guozhen Wang ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Cold Drawing ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Fiber Morphology ◽  
Molding Process ◽  
Butylene Succinate ◽  
Low Frequencies ◽  
Biodegradable Poly

In this study, biodegradable poly(butylene succinate)/poly(lactic acid) (PBS/PLA) in-situ submicrofibrillar composites with various PLA content were successfully produced by a triple-screw extruder followed by a hot stretching−cold drawing−compression molding process. This study aimed to investigate the effects of dispersed PLA submicro-fibrils on the thermal, mechanical and rheological properties of PBS/PLA composites. Morphological observations demonstrated that the PLA phases are fibrillated to submicro-fibrils in the PBS/PLA composites, and all the PLA submicro-fibrils produced seem to have a uniform diameter of about 200nm. As rheological measurements revealed, at low frequencies, the storage modulus (G’) of PBS/PLA composites has been increased by more than four orders of magnitude with the inclusion of high concentrations (15 wt % and 20 wt %) of PLA submicro-fibrils, which indicates a significant improvement in the elastic responses of PBS melt. Dynamic Mechanical Analysis (DMA) results showed that the glass transition temperature (Tg) of PBS phase slightly shifted to the higher temperature after the inclusion of PLA. DSC experiments proved that fiber morphology of PLA has obvious heterogeneous nucleation effect on the crystallization of PBS. The tensile properties of the PBS/PLA in-situ submicrofibrillar composites are also improved compared to neat PBS.

scholarly journals Effect of Hydrophobic Excipients on the Release Behavior of Dexamethasone and Betamethasone from Biodegradable Poly (DL-lactide) Polymeric Implants

1970 ◽  
Vol 45 (3) ◽  
pp. 189-196
Author(s):  
Fariba Khan ◽  
Tasnuva Mahmud ◽  
M Saiful Islam ◽  
Reza-ul Jalil
Keyword(s):  
Lactic Acid ◽  
Sustained Release ◽  
Sodium Phosphate ◽  
In Vitro Dissolution ◽  
Poly Lactic Acid ◽  
Release Mechanism ◽  
Biodegradable Poly ◽  
Sorbitan Esters ◽  
Betamethasone And Dexamethasone

This study was conducted with the aim of formulating injectable in-situ forming implants of biodegradable poly (D,L-poly lactic acid) (DLPLA) with steroidal drugs. Two steroidal drugs betamethasone sodium phosphate and dexamethasone sodium phosphate were selected as model drug. Different hydrophobic excipients such as sorbitan esters of lauric acid (Span 20), sorbitan esters of oleic acid (Span 80), cetyl alcohol, glyceryl monostearate, glyceryl dibehenate (CompritolAT088®), glyceryl palmito-stearic ester (Precirol®) were used. In-vitro dissolution of 7 days was performed to investigate the effect of these excipients on the release of betamethasone and dexamethasone from insitu forming DL-PLA implants. Drug release data were fitted in different models to characterize release mechanism. Both betamethasone and dexamethasone release were found to follow Korsmeyer model. Glyceryl palmitostearate was found to reduce the release of both betamethasone and dexamethasone most. Time for 25% release (t25), 50% release (t50), and 75% release (t75) of the drugs were calculated. Mean dissolution time (MDT) values were also calculated from the dissolution data. MDT (day) was 2.48±0.2 and 2.31±0.3 for betamethasone and dexamethasone respectively for implants containing no excipient. Incorporation of all the excipients (except span 20) increased these MDT values for both of the drugs indicating sustained release nature of the excipients. Key words: In-situ implants; Poly (D,L-lactic acid); Betamethasone; Dexamethasone; Hydrophobic excipients; Sustained release DOI: 10.3329/bjsir.v45i3.6527Bangladesh J. Sci. Ind. Res. 45(3), 189-196, 2010

Biodegradable Poly(Lactic Acid)/Organic-Montmorillonite Nanocomposites: Preparation and Characterization

2009 ◽  
Vol 87-88 ◽  
pp. 422-426 ◽  
Author(s):  
Na Li Chen ◽  
Hui Xia Feng ◽  
He Ming Luo ◽  
Dan Zhao ◽  
Jian Hui Qiu
Keyword(s):  
Lactic Acid ◽  
In Situ Polymerization ◽  
Interlayer Spacing ◽  
Poly Lactic Acid ◽  
Organic Montmorillonite ◽  
Heat Distortion Temperature ◽  
Biodegradable Poly ◽  
Ft Ir ◽  
Silicate Layers

In this work, the biodegradable poly(lactic acid) (PLA)/organic-montmorillonite (O-MMT) nanocomposites were successfully prepared by the in situ polymerization intercalation process of D,L-lactide with organically-modified montmorillonite which was first treated by Cu cations and second treated by n-hexadecyl trimethylammonium bromide (CTAB) cations. O-MMT was characterized by FT-IR and XRD, the results showed that Cu cations and CTAB cations had been inserted to the interlayer of MMT, and the interlayer spacing of CTAB-Cu-MMT (O-MMT) increased by 1.829nm. The biodegradable PLA/O-MMT nanocomposites were characterized by XRD, SEM, FT-IR, TG, and the results showed that silicate layers were intercalated into the PLA matrix and the biodegradable PLA/O-MMT nanocomposites were of two different types: intercalated nanocomposites and exfoliated nanocomposites. This new nanocomposites frequently exhibited remarkable improvements when compared with the neat PLA matrix. Improvements could include increased heat distortion temperature, an increase in the biodegradability rate of biodegradable polymers.

Peculiar crystallization kinetics of biodegradable poly(lactic acid)/poly(propylene carbonate) blends

2015 ◽  
Vol 55 (12) ◽  
pp. 2698-2705 ◽  
Author(s):  
Maria Laura Di Lorenzo ◽  
Roxanne Ovyn ◽  
Mario Malinconico ◽  
Paolo Rubino ◽  
Yves Grohens
Keyword(s):  
Lactic Acid ◽  
Propylene Carbonate ◽  
Crystallization Kinetics ◽  
Poly Lactic Acid ◽  
Biodegradable Poly ◽  
Poly Propylene ◽  
Kinetics Of
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