Surface Modification of Poly(Lactic Acid) Microspheres via Gamma Irradiation

2017 ◽  
Vol 264 ◽  
pp. 128-131 ◽  
Author(s):  
Zahroh Hasanah Augustini Ninaya ◽  
Zuratul Ain Abdul Hamid
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Gamma Irradiation ◽  
Polymer Surface ◽  
Poly Lactic Acid ◽  
Γ Irradiation ◽  
Sem Images ◽  
Dose Irradiation ◽  
Before And After ◽  
The Difference

Irradiation technique is one of methods used in modification of polymer surface although it has been used in sterilization for decades. It allows establishing simple and compact technique, non-contaminated with residues of toxic initiators, crossing agents or other additives. This study is to evaluate the effects of different gamma (γ) irradiation doses on poly (lactic acid) (PLA) microsphere surface grafted with maleic anhydride (MAH). Source of γ-irradiation used is 60Co and dose irradiation used in this study is10, 30, 50, 70, 90 and 110 kGy. Characterization was performed on samples before and after irradiation by FTIR, SEM and DSC. Results of FTIR suggest maleic anhydride successfully grafted onto PLA microsphere. Data from DSC shows thermal property of PLA changed after irradiation where the crystallization is increased compared to neat PLA. SEM images showed the difference of the PLA microspheres before and after γ irradiation. Neat PLA microspheres had a smooth surface, while after irradiation, the surface become rough. Degradation of microspheres observed by SEM as in suggest that PLA microspheres is degrade by bulk degradation. Gamma irradiation not only modified the surface of PLA microspheres by successfully grafting the maleic anhydride and increase surface roughness, it also affected the bulk properties of PLA microspheres.

Photolytic and thermal annealing of radical anions gamma-irradiated monocarboxylic acids

1979 ◽  
Vol 44 (12) ◽  
pp. 3632-3643 ◽  
Author(s):  
Karel Mach ◽  
Igor Janovský ◽  
Karel Vacek
Keyword(s):  
Thermal Annealing ◽  
Pivalic Acid ◽  
Esr Spectra ◽  
Paramagnetic Species ◽  
Radical Anions ◽  
Γ Irradiation ◽  
Before And After ◽  
Optical Bleaching ◽  
The Difference ◽  
Gamma Irradiated

Total yields of paramagnetic species, their optical bleaching and thermal annealing in acetic, propionic, a-butyric, isobutyric, and pivalic acid γ-irradiated at 77 K were followed by ESR spectroscopy. Radical anions, always found after irradiation, disappear during optical bleaching without formation of any paramagnetic product. During thermal annealing they are converted almost quantitatively into the α-radicals of the respective acid, with the exception of pivalic acid. Amounts of radical anions were estimated from the difference of integrated ESR spectra taken before and after optical bleaching. The results show that approximately equal amounts of the reduction and oxidation paramagnetic products of the γ-irradiation can be detected.

scholarly journals The combined plasticization of jute and tung oil anhydride for jute fiber reinforced poly(lactic acid) composites

2021 ◽  
pp. 096739112110576
Author(s):  
Ying Zhou ◽  
Can Chen ◽  
Lan Xie ◽  
Xiaolang Chen ◽  
Guangqiang Xiao ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical And Mechanical Properties ◽  
Complex Viscosity ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Sem Images ◽  
Pseudoplastic Fluid ◽  
Tung Oil ◽  
Biodegradable Poly ◽  
The Impact

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.

scholarly journals Styrene-Assisted Maleic Anhydride Grafted Poly(lactic acid) as an Effective Compatibilizer for Wood Flour/Poly(lactic acid) Bio-Composites

Polymers ◽  
2017 ◽  
Vol 9 (11) ◽  
pp. 623 ◽  
Author(s):  
Jun Du ◽  
Youyong Wang ◽  
Xinfeng Xie ◽  
Min Xu ◽  
Yongming Song
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Wood Flour ◽  
Poly Lactic Acid

scholarly journals Investigation on compatibility of PLA/PBAT blends modified by epoxy-terminated branched polymers through chemical micro-crosslinking

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 39-54 ◽  
Author(s):  
Bo Wang ◽  
Yujuan Jin ◽  
Kai’er Kang ◽  
Nan Yang ◽  
Yunxuan Weng ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Sem Analysis ◽  
Branched Polymers ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Butylene Terephthalate ◽  
The Difference ◽  
Physical And Chemical ◽  
The Impact

AbstractIn this study, a type of epoxy-terminated branched polymer (ETBP) was used as an interface compati- bilizer to modify the poly lactic acid (PLA)/poly(butylene adipate-co-butylene terephthalate) (PBAT) (70/30) blends. Upon addition of ETBP, the difference in glass transition temperature between PLA and PBAT became smaller. By adding 3.0 phr of ETBP, the elongation at break of the PLA/PBAT blends was found increased from 45.8% to 272.0%; the impact strength increased from 26.2 kJ·m−2 to 45.3 kJ·m−2. In SEM analysis, it was observed that the size of the dispersed PBAT particle decreased with the increasing of ETBP content. These results indicated that the compatibility between PLA and PBAT can be effectively enhanced by using ETBP as the modifier. The modification mechanism was discussed in detail. It proposes that both physical and chemical micro-crosslinking were formed, the latter of which was confirmed by gel content analysis.

Characterization of Electrospun Poly(Lactic Acid)/polyaniline Blend Nanofibers

2011 ◽  
Vol 332-334 ◽  
pp. 317-320 ◽  
Author(s):  
Hui Qin Zhang
Keyword(s):  
Lactic Acid ◽  
Composite Nanofibers ◽  
Weight Ratio ◽  
Electrospinning Process ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Ft Ir

In this study, composite nanofibers of polyaniline doped with dodecylbenzene sulfonic acid (PANI-DBSA) and Poly(lactic acid) (PLA) were prepared via an electrospinning process. The surface morphology, thermal properties and crystal structure of PLA/PANI-DBSA nanofibers are characterized using Fourier transform infrared spectroscopy (FT-IR), wide-angle x-ray diffraction (WAXD) and scanning electron microscopy (SEM). SEM images showed that the morphology and diameter of the nanofibers were affected by the weight ratio of blend solution.

Preparation and Characterization of Poly(Lactic Acid)-g-Maleic Anhydride + Starch Blends

2009 ◽  
Vol 277 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Victor H. Orozco ◽  
Witold Brostow ◽  
Wunpen Chonkaew ◽  
Betty L. López
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Poly Lactic Acid ◽  
Starch Blends

Rheology of poly(lactic acid)/poly(trimethylene terephthalate) blends compatibilized by clay or maleic anhydride-grafted poly(ethylene-octene) elastomer

2019 ◽  
Vol 39 (3) ◽  
pp. 248-253
Author(s):  
Gwo-Geng Lin ◽  
Yi-Hu Song ◽  
Chao-Tsai Huang ◽  
Marek Sipos ◽  
Zhaokang Tu
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Low Frequency ◽  
Complex Viscosity ◽  
Fold Increase ◽  
Poly Lactic Acid ◽  
Morphology Evolution ◽  
Cloisite 30B ◽  
Trimethylene Terephthalate ◽  
Poly Ethylene

Abstract Blends of two biobased polymers, poly(lactic acid) and poly(trimethylene terephthalate) (PTT), were compatibilized with either maleic anhydride-grafted poly(ethylene-octene) (mPOE) or organically modified clay (Cloisite 30B). Dynamic rheological measurements revealed that the mPOE inclusion resulted in a four-fold increase in viscosity relative to the noncompatibilized blends. By loading 3 wt% Cloisite 30B, the storage moduli of the blends showed a distinct solid-like behavior and high complex viscosity in the low-frequency region, which can be interpreted by the reduced sizes of the PTT phase evidenced from the scanning electron microscopy (SEM) micrography. A temperature sweep of the viscosity of the blends starting from 180°C revealed that the existence of an unmelted PTT dispersed phase might impede the decline in viscosity with increasing temperature near the melting point of PTT. The introduced compatibilizers can restrict the temperature-dependent morphology evolution, and the use of the 3 wt% 30B clay can prohibit the morphology evolution during the temperature sweep.

The effect of different peroxides on physical and chemical properties of poly(lactic acid) modified with maleic anhydride

Polymer ◽  
2019 ◽  
Vol 179 ◽  
pp. 121669 ◽  
Author(s):  
Talita R. Rigolin ◽  
Lidiane C. Costa ◽  
Tiago Venâncio ◽  
Bruno Perlatti ◽  
Sílvia H.P. Bettini
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Chemical Properties ◽  
Poly Lactic Acid ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

Method of quantifying the loss of acidification activity of lactic acid starters during freezing and frozen storage

2000 ◽  
Vol 67 (1) ◽  
pp. 83-90 ◽  
Author(s):  
FERNANDA FONSECA ◽  
CATHERINE BÉAL ◽  
GEORGES CORRIEU
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Storage Time ◽  
Frozen Storage ◽  
Operating Conditions ◽  
Linear Relationships ◽  
Before And After ◽  
Acidification Activity ◽  
The Difference ◽  
And Storage

We have developed a method to quantify the resistance to freezing and frozen storage of lactic acid starters, based on measuring the time necessary to reach the maximum acidification rate in milk (tm) using the Cinac system. Depending on the operating conditions, tm increased during the freezing step and storage. The loss of acidification activity during freezing was quantified by the difference (Δtm) between the tm values of the concentrated cell suspension before and after freezing. During storage at −20 °C, linear relationships between tm and the storage time were established. Their slope, k, allowed the quantitation of the decrease in acidification activity during 9–14 weeks of frozen storage. The method was applied to determine the resistance to freezing and frozen storage of four strains of lactic acid bacteria and to quantify the cryoprotective effect of glycerol.

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