Constrained nonlinear optimization for solubility parameters of poly(lactic acid) and poly(glycolic acid)—validation and comparison

Agrawal, Abhishek; Saran, Amit D.; Rath, Swagat S.; Khanna, Ashok

doi:10.1016/j.polymer.2004.10.022

Cited by 81 publications

(58 citation statements)

References 10 publications

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“…Methylene dichloride is a reported as good solvent for PLA. 24 So it was likely that the particles were the reaction product of HBP and PA. The reaction of HBP and PA could form cross-linked network because of their multifunctionality and make them insoluble in a solvent.…”

Section: Resultsmentioning

confidence: 99%

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

2007

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The inherent brittleness of polylactide (PLA) poses considerable scientific challenges and limits its large-scale applications. Here, we propose and demonstrate a new industrially relevant methodology to develop a polylactide (PLA)-based nanoblend having outstanding stiffness-toughness balance. In this approach, a hydroxyl functional hyperbranched polymer (HBP) was in-situ cross-linked with a polyanhydride (PA) in the PLA matrix during melt processing. There was formation of new hyperbranched polymer-based cross-linked particles in the PLA matrix. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed the sea-island morphology of PLA-cross-linked HBP blend. The domain size of cross-linked HBP particles in the PLA matrix was less than 100 nm as obtained from TEM. The presence of cross-linked hyperbranched polymer in the PLA matrix exhibited ∼570% and ∼847% improvement in the toughness and elongation at break, respectively, as compared to unmodified PLA. The increase in the ductility of modified PLA was related to stress whitening and multiple crazing initiated in the presence of cross-linked HBP particles. Formation of a networked interface as revealed by rheological data was associated with enhanced compatibility of the PLA-cross-linked HBP blend as compared to the PLA/HBP blend. The cross-linking reaction of HBP with PA was confirmed with the help of Fourier transform infrared spectroscopy (FTIR) and low-temperature dynamical mechanical thermal analysis (DMTA).

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Section: Resultsmentioning

confidence: 99%

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

2007

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“…b The partial solubility parameters of PLA calculated using the constrained nonlinear optimization method of Agrawal et al (2004).…”

Section: Discussionmentioning

confidence: 99%

Preparation of biodegradable polymeric nanoparticles for pharmaceutical applications using glass capillary microfluidics

Othman

Vladisavljević

Nagy

2015

Chemical Engineering Science

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The aim of this study was to develop a new microfluidic approach for the preparation of nanoparticles with tuneable sizes based on micromixing / direct nanoprecipitation in a coaxial assembly of tapered-end glass capillaries. The organic phase was 1 wt% poly(-caprolactone) (PCL) or poly(dl-lactic acid) (PLA) in tetrahydrofuran and the antisolvent was Milli-Q water.The size of nanoparticles was precisely controlled over a range of 190-650 nm by controlling phase flow rates, orifice size and flow configuration (two-phase co-flow or countercurrent flow focusing). Smaller particles were produced in a flow focusing device, because the organic phase stream was significantly narrower than the orifice and remained narrow for a longer distance downstream of the orifice. The mean size of PCL particles produced in a flow focusing device with an orifice size of 200 m, an organic phase flow rate of 1.7 mL h -1 and an aqueous-toorganic flow rate ratio of 10 was below 200 nm. The size of nanoparticles decreased with decreasing the orifice size and increasing the aqueous-to-organic phase flow rate ratio. Due to *Revised Manuscript Click here to view linked References 2 higher affinity for water and amorphous structure, PLA nanoparticles were smaller and exhibited a smoother surface and more rounded shape than PCL particles.

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“…In all the cases the high effect of polar interaction of [93] ; DME and HCFC-22 [21] ; others properties [80] Copyright the systems is shown (to also see the system DL-PLA-HFC134a in the Figure 14). It is worth to note that for all polymer þ DME mixtures under study in this work, the solubility parameter of DME, in the literature data, seems to be overestimated.…”

Section: Biopolymersmentioning

confidence: 94%

Polymer Chain Collapse in Supercritical Fluids. 2. Experimental Evidence

Ortiz-Estrada

Luna‐Bárcenas

Alvarado

et al. 2009

Macromolecular Symposia

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Summary:The phase behavior of a polymer in a supercritical solvent at the LCST equilibrium limits is described in this work, in the proximity of u point, proposing the use of a conformational parameter, C. The results obtained by molecular simulation in an NVT ensemble have been correlated by extensive, varied experimental information. The relationship between polymer/solvent solubility parameters has shown that the behavior of these systems is a function of the energetic structure-interaction relationship between the polymer chain and the solvent. C results in a generalized parameter indicative of the phase stability of the solution. At greater magnitudes, the solution becomes unstable, requiring elevated pressure to stabilize. However, stable solutions are found at lower pressures when C approaches 1. The experimental evidence, together with the determination of the solubility parameter with the Sanchez-Lacombe equation (also obtained from the literature) strengthens this observation. The analysis of the polar contribution on the Hansen Parameter (HSP) enables their effect to be studied in systems where high polar interactions between the polymer and solvent (as in the case of biopolymers) are expected.

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Constrained nonlinear optimization for solubility parameters of poly(lactic acid) and poly(glycolic acid)—validation and comparison

Cited by 81 publications

References 10 publications

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

Modification of Brittle Polylactide by Novel Hyperbranched Polymer-Based Nanostructures

Preparation of biodegradable polymeric nanoparticles for pharmaceutical applications using glass capillary microfluidics

Polymer Chain Collapse in Supercritical Fluids. 2. Experimental Evidence

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