scholarly journals Biodegradable Blends of Grafted Dextrin with PLGA-block-PEG Copolymer as a Carrier for Controlled Release of Herbicides into Soil

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 832 ◽  
Author(s):  
Kamila Lewicka ◽  
Piotr Rychter ◽  
Małgorzata Pastusiak ◽  
Henryk Janeczek ◽  
Piotr Dobrzynski

The presented work aimed to test influence of poly(L-lactide-co-glycolide)-block-poly (ethylene oxide) copolymer modification by blending with grafted dextrin or maltodextrin on the course of degradation in soil and the usefulness of such material as a matrix in the controlled release of herbicides. The modification should be to obtain homogenous blends with better susceptibility to enzymatic degradation. Among all tested blends, which were proposed as a carrier for potential use in the controlled release of plant protection agents, PLGA-block-PEG copolymer blended with grafted dextrin yielded very promising results for their future applications, and what is very importantly proposed formulations provide herbicides in unchanged form into soil within few months of release. The modification PLAGA/PEG copolymer by blending with modificated dextrins affects the improvement of the release profile. The weekly release rates for both selected herbicides (metazachlor and pendimethalin) were constant for a period of 12 weeks. Enzymatic degradation of modified dextrin combined with leaching of the degradation products into medium caused significant erosion of the polymer matrix, thereby leading to acceleration of water diffusion into the polymer matrix and allowing for easier leaching of herbicides outside the matrix.

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Tran Duy Thanh ◽  
Nguyen Dang Mao ◽  
Nguyen Thi Kim Ngan ◽  
Ha Thuc Chi Nhan ◽  
Ha Thuc Huy ◽  
...  

In recent years, polymer clay nanocomposites have been attracting considerable interests in polymers science because of their advantages. There are many scientists who researched about this kind of material and demonstrated that when polymer matrix was added to little weight of clay, properties were enhanced considerably. Because clay is a hydrophilic substance so it is difficult to use as filler in polymer matrix having hydrophobic nature, so clay needs to be modified to become compatible with polymer. In this study, poly(ethylene oxide) was used as a new modifier for clay to replace some traditional ionic surfactants such as primary, secondary, tertiary, and quaternary alkyl ammonium or alkylphosphonium cations having the following disadvantages: disintegrate at high temperature, catalyze polymer degradation, and make nanoproducts colorific, and so forth. In order to evaluate modifying effect of poly(ethylene oxide), modified clay products were characterize d by X-ray spectrum. Then organoclay was used to prepare nanocomposite based on unsaturated polyester. Morphology and properties of nanocomposites were measure d by X-ray diffraction, transmission electron microscopy, tensile strength, and thermal stability. The results showed that clay galleries changed to intercalated state in the nanocomposites. Properties of nanocomposites were improved a lot when the loading of the organoclay was used at 1 phr.


2016 ◽  
Vol 27 (19) ◽  
pp. 195706 ◽  
Author(s):  
R Porras ◽  
D V Bavykin ◽  
J Zekonyte ◽  
F C Walsh ◽  
R J Wood

Author(s):  
Shamo Zokhrab Tapdiqov

Doxycycline was loaded with synthesized micelles composed of methyl Poly (ethylene glycol-block-poly (L-alanine–co–L-aspartate), or mPEG–Ala–Asp, and then characterized as a drug delivery carrier. The synthesis of the temperature-sensitive mPEG–Ala–Asp block copolymer was carried out by two-step ring-opening polymerization: firstly, the mPEG reacts with L-alanine N-carboxylic anhydride, and secondly the resulting mPEG–Ala reacts with benzyl aspartate N-carboxylic anhydride. The molecular structure of the copolymers obtained was determined by FT-IR and NMR spectroscopy methods and the micelles were characterized by SEM, TEM and DLS, respectively. The controlled release of Dox from hydrogel in the presence of PBS (8 to 9% by weight) lasts 6 to 7 days exhibiting stable release rates. The drug release mechanisms were studied: Higuchi and zero order models. The results and correlation coefficients applied to the Higuchi and zero-order models. The findings show the potential use of mPEG–Ala–Asp as an effective depot matrix to deliver anthracycline class drugs.


Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1263 ◽  
Author(s):  
Jaroslav Kousal ◽  
Jana Sedlaříková ◽  
Zuzana Kolářová-Rašková ◽  
Zdeněk Krtouš ◽  
Liliana Kučerová ◽  
...  

Poly(ethylene oxide) (PEO)-like thin films were successfully prepared by plasma-assisted vapor thermal deposition (PAVTD). PEO powders with a molar weight (Mw) between 1500 g/mol and 600,000 g/mol were used as bulk precursors. The effect of Mw on the structural and surface properties was analyzed for PEO films prepared at a lower plasma power. Fourier transform (FTIR-ATR) spectroscopy showed that the molecular structure was well preserved regardless of the Mw of the precursors. The stronger impact of the process conditions (the presence/absence of plasma) was proved. Molecular weight polydispersity, as well as wettability, increased in the samples prepared at 5 W. The influence of deposition plasma power (0–30 W) on solubility and permeation properties was evaluated for a bulk precursor of Mw 1500 g/mol. The rate of thickness loss after immersion in water was found to be tunable in this way, with the films prepared at the highest plasma power showing higher stability. The effect of plasma power deposition conditions was also shown during the permeability study. Prepared PEO films were used as a cover, and permeation layers for biologically active nisin molecule and a controlled release of this bacteriocin into water was achieved.


Fibers ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 56 ◽  
Author(s):  
Nafeesa Mohd Kanafi ◽  
Norizah Abdul Rahman ◽  
Nurul Husna Rosdi ◽  
Hasliza Bahruji ◽  
Hasmerya Maarof

The potential use of carboxymethyl sago pulp (CMSP) extracted from sago waste for producing hydrogel nanofibers was investigated as a methylene blue drug carrier. Sago pulp was chemically modified via carboxymethylation reaction to form carboxymethyl sago pulp (CMSP) and subsequently used to produce nanofibers using the electrospinning method with the addition of poly(ethylene oxide) (PEO). The CMSP nanofibers were further treated with citric acid to form cross-linked hydrogel. Studies on the percentage of swelling following the variation of citric acid concentrations and curing temperature showed that 89.20 ± 0.42% of methylene blue (MB) was loaded onto CMSP hydrogel nanofibers with the percentage of swelling 4366 ± 975%. Meanwhile, methylene blue controlled release studies revealed that the diffusion of methylene blue was influenced by the pH of buffer solution with 19.44% of MB released at pH 7.34 within 48 h indicating the potential of CMSP hydrogel nanofibers to be used as a drug carrier for MB.


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