Crystal structure and biodegradation of aliphatic polyester crystals

Iwata, Tadahisa; Doi, Yoshiharu

doi:10.1002/(sici)1521-3935(19991101)200:11<2429::aid-macp2429>3.0.co;2-#

Cited by 140 publications

(125 citation statements)

References 91 publications

(138 reference statements)

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“…For example, poly[(R)-3-hydroxybutanoic acid] is biodegradable, whereas its enantiomer is not. 20 Therefore, it is essential to make a polymer with precise chirality control if the polymer is used in an ecosystem. Stereocomplex formation is another attractive feature of chiral polymers.…”

Section: What Happens When a Polymer Is Chiral?mentioning

confidence: 99%

Asymmetric polymerization using C1 resources

Nozaki

2003

J. Polym. Sci. A Polym. Chem.

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Section: What Happens When a Polymer Is Chiral?mentioning

confidence: 99%

Asymmetric polymerization using C1 resources

Nozaki

2003

J. Polym. Sci. A Polym. Chem.

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“…There are many articles in which the effect of crystallinity of the sample on its biodegradability was pointed out. 17,18 Generally speaking, highly crystalline polyester samples tend to inhibit their smooth degradation by microorganisms, regardless of its chemical structure. It was already noted that rising-up of T g was observed as increasing of the E-configuration fraction (Table I).…”

Section: Biochemical Oxygen Demand Testmentioning

confidence: 99%

Effects of Geometrical Difference of Unsaturated Aliphatic Polyesters on Their Biodegradability II. Isomerization of Poly(maleic anhydride-co-propylene oxide) inthe Presence of Morpholine

Takenouchi

Takasu

Inai

et al. 2002

Polym J

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ABSTRACT:Ring-opening copolymerizations of succinic anhydride (SAn, 1) or maleic anhydride (MAn, 2) with propylene oxide (PO) were carried out by using magnesium diethoxide (Mg(OEt) 2 ) as a catalyst. The unsaturated polyester (P2a) was found to have only Z-configuration around a C=C double bond from its 1 H and 13 C NMR spectra. Isomerization reaction of P2a from Z-to E-configuration was performed in 1,2-dichloroethane with a catalytic amount of morpholine. Thus unsaturated polyesters, P2b-e, having the same molecular weight but the different ratio of Z-/E-configuration could be optionally prepared from one original polymer P2a by controlling isomerization reaction time. Biodegradability of these polyester samples was evaluated from their biochemical oxygen demand (BOD) values in the presence of an activated sludge. Polyester P2a was hardly degraded during measurement. However, polyesters P2b-e, partially containing E-configuration of the C=C double bond, degraded considerably faster than P2a itself. The biodegradability of saturated polyester P1 was also examined to compare with the P2-series.KEY WORDS Biodegradability / Unsaturated Polyester / Geometrical Isomer / Ring-Opening Copolymerization / Cyclic Acid Anhydride / Propylene Oxide / Synthetic polymeric materials have provided many advantages in our daily life for the last century, and become one of the most important materials. When once almost all of synthetic polymers are disposed after use, however, those cause serious environmental problems. Thus, biodegradable polymers have received much attention in recent years as one of the answer to solve the problems. In fact, biodegradable polymers, especially aliphatic polyesters, have been widely investigated by many scientists in the world.In spite of a large number of studies on biodegradability of polyesters, little attention has been given to unsaturated polyesters. 1-6 Tokiwa and Suzuki reported that a few unsaturated polyesters containing 2-butenediol unit could be hydrolyzed by lipase. 1 On the other hand, slightly cross-linked unsaturated polyesters, poly(hexamethylene fumarate) and poly(cis-2-butene fumarate), were hardly hydrolyzed by lipase.A carbon-carbon double bond in unsaturated polyesters has two geometrical isomers (Z-and Econfiguration), and such difference should affect their biodegradability. In controlling the biodegradation rate of polyester, it is very helpful to make geometrical effects clear. In our previous paper, 6 it was shown that in comparison with saturated polyesters, the ef- † To whom correspondence should be addressed. ficient degradation was prevented by introducing Zconfiguration of C=C double bond in the unsaturated polyesters but introducing E-configuration did not affect so remarkably. However, the variety of samples was limited because of the difficulty in preparation of samples having the same molecular weight and the different Z/E ratio. Although polycondensation method of unsaturated acid anhydrides with diol in the presence of acid as a catalyst was employed in prev...

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“…PHB synthesized by bacteria is a biodegradable thermoplastic. [1][2][3][4][5][6][7] PHB has received much attention as a environmentally friendly material because of its thermoplasticity coupled with its biodegradability. However, it has been recognized that PHB is often too rigid and stiff for many applications because of the perfectly isotactic structure consisting exclusively of the R configuration.…”

Section: Introductionmentioning

confidence: 99%

“…PLLA produced from renewable resources, such as starch, also is a biodegradable and biocompatible thermoplastic. [7][8][9][10][11] PLLA has already been used in various applications, especially in the medical field, because of its superior biocompatibility. The crystalline structures of PHB and PLLA have been established as orthorhombic systems by means of wide angle X-ray diffraction (WAXD).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Homogeneity of Binary Blends of Poly(3-hydroxybutyrate) and Poly(l-lactic acid) Studied by Near Infrared Chemical Imaging (NIRCI)

et al. 2007

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IntroductionPoly((R)-3-hydroxybutyrate) (PHB) and poly(L-lactic acid) (PLLA) are well-studied aliphatic biodegradable polymers. PHB synthesized by bacteria is a biodegradable thermoplastic. [1][2][3][4][5][6][7] PHB has received much attention as a environmentally friendly material because of its thermoplasticity coupled with its biodegradability. However, it has been recognized that PHB is often too rigid and stiff for many applications because of the perfectly isotactic structure consisting exclusively of the R configuration. PLLA produced from renewable resources, such as starch, also is a biodegradable and biocompatible thermoplastic. [7][8][9][10][11] PLLA has already been used in various applications, especially in the medical field, because of its superior biocompatibility. The crystalline structures of PHB and PLLA have been established as orthorhombic systems by means of wide angle X-ray diffraction (WAXD). 12-16The thermal behavior of PHB and PLLA have also been investigated by infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and WAXD. [17][18][19][20][21][22] The physical and mechanical properties of PHB and PLLA are not always suitable for practical applications. Several modifications have been proposed to improve their processing and mechanical properties, such as copolymerization and blending with other biodegradable polymers. Compared to copolymerization methods, physical blending is an easier and faster way to manipulate the desired properties of polymeric materials. Several studies of the miscibility and morphology for PHB/PLLA blends have been published. [23][24][25][26][27][28][29][30] In our previous studies, the miscibility and dispersibility of PHB/PLLA blends were revealed by IR and Raman microspectroscopy. 29,30 These studies showed that the PHB component is always crystallized in the blends irrespective of the blend ratio, and that both components are mixed in the nonspherulite parts. However, these studies were carried out in only some localized spots of samples with different morphology by using polarized light microscopy. Thus, the blends were not analyzed in much wider areas encompassing the entire composite material.Near infrared (NIR) spectroscopy is widely used as a tool for materials characterization. [31][32][33][34] In the NIR region (800 -2500 nm), the overtone and combination bands of the C-H, O-H, and N-H stretching and deformation vibrational modes provide highly specific molecular information for species identification. Sample preparation and handling are relatively straightforward for NIR spectroscopy. Multivariate data analysis has also accelerated the application of NIR spectroscopy. [35][36][37][38] Therefore, NIR spectroscopy has often been adopted as a useful probe in studying polymers. For example, the isothermal crystallization kinetics of PHB was investigated by NIR spectroscopy. 39 An NIR on-line monitoring system has proven to be useful in the quantitative analysis of the molten polyolefin polymers [40][41][42][43] and in the tracking of the ...

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Crystal structure and biodegradation of aliphatic polyester crystals

Cited by 140 publications

References 91 publications

Asymmetric polymerization using C1 resources

Asymmetric polymerization using C1 resources

Effects of Geometrical Difference of Unsaturated Aliphatic Polyesters on Their Biodegradability II. Isomerization of Poly(maleic anhydride-co-propylene oxide) inthe Presence of Morpholine

Evaluation of Homogeneity of Binary Blends of Poly(3-hydroxybutyrate) and Poly(l-lactic acid) Studied by Near Infrared Chemical Imaging (NIRCI)

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