Synthesis, Solid-State Structure, and Surface Properties of End-Capped Poly(<scp>l</scp>-lactide)

Kobori, Yuka; Iwata, Tadahisa; Doi, Yoshiharu; Abe, Hideki

doi:10.1021/bm034382n

Cited by 28 publications

(33 citation statements)

References 30 publications

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“…Although there is a broad interval of values reported for the melting enthalpy of pure PLLA 100% crystalline [32][33], the most commonly used value, taken by us for calculations, is close to 93 J/g [34][35][36][37].…”

Section: Thermal Properties Of the Pcl-b-plla Di-blocksmentioning

confidence: 87%

Effect of the molecular weight on the crystallinity of PCL-b-PLLA di-block copolymers

Peponi

Navarro-Baena

Báez

et al. 2012

Polymer

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A systematic study on the synthesis and characterization of di-block copolymers based on aliphatic polyesters such as poly(L-lactic acid) (PLLA) and poly(-caprolactone) (PCL), performed varying both the length of the blocks as well as the relative content of each block in the copolymers, is reported. The block-length and the molecular weight of each synthesized PCL-b-PLLA di-block copolymer were analyzed by nuclear magnetic resonance spectroscopy. The influence of the block length and of the amount of each block on the thermal properties and the morphology, was evaluated by differential scanning calorimetry and by small angle X-Ray scattering experiments. In particular, the correlation between the molecular weight of each block and its amorphous and/or crystalline structure was obtained, evidencing that the crystallization of the PLLA block was not influenced by the presence of PCL and depends mainly on its molecular weight but the crystallization of PCL is strongly interfered by the crystallization of PLLA. In particular PLLA blocks are amorphous for short lengths (≤ 672 g/mol, that means ≤ 9.3 LA repeat units) and start to crystallize for molecular weight ≥ 964 g/mol, that means ≥ 13.4 LA repeat units.

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Section: Thermal Properties Of the Pcl-b-plla Di-blocksmentioning

confidence: 87%

Effect of the molecular weight on the crystallinity of PCL-b-PLLA di-block copolymers

Peponi

Navarro-Baena

Báez

et al. 2012

Polymer

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“…In this manner 25 the PLLA blocks were linked through urethane bonds. The formation of the urethane bonds was confirmed by FT-IR analysis.…”

Section: Synthesis Of Poly(ester-urethane)smentioning

confidence: 99%

“…The degree of 50 crystallinity (X c ) has been estimated considering the value of the melting enthalpy of 100 % crystalline PLLA around 93 KJ/mol 25 while for the PCL a value of 148 KJ/mol 26 is considered. The DSC thermograms for the synthesized tri-block copolymers are reported in Fig.…”

Section: Crystallisation Analysismentioning

confidence: 99%

“…30 In Fig. 8 the thermograms corresponding to the second heating 25 scan of the poly(ester-urethane)s synthesized from the tri-block copolymers are reported. Striking differences on the melting temperatures as well as on the degree of crystallinity compared with the initial tri-block copolymers have been obtained on the poly(ester-urethane)s as 30 shown in Table 3, where the amounts of HDI in the poly(esterurethane)s are reported in order to easily understand the effects of the urethane bonds on the thermal properties.…”

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confidence: 99%

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Synthesis of PLLA-b-PCL-b-PLLA linear tri-block copolymers and their corresponding poly(ester-urethane)s: effect of the molecular weight on their crystallisation and mechanical properties

et al. 2014

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With the general objective to design polymer based materials with specific thermal and mechanical properties, a systematic study on the crystallinity and the mechanical properties of synthesized linear tri-block copolymers based on poly(L-lactic acid) and poly(ε -caprolactone) and of their corresponding poly(ester-urethane)s has been performed. In particular, eleven tri-block copolymers were 10 synthesized varying both the molecular weight of the blocks as well as the relative content of each block in the copolymer, focusing the attention on the relationship between their chemical compositions and their tailored final properties in order to tune them taking into account their possible applications (i.e. as shape memory materials). From them, eleven poly(ester-urethane)s were synthesized by condensation with hexamethylene diisocyanate (HDI). The chemical composition of the synthesized polymers was studied and correlated with their thermal and crystalline properties obtained by both dynamic scanning calorimetry (DSC) and small angle X-ray diffraction 15 (SAXS) experiments. The relationship between their crystalline structure, thermal and mechanical properties with the molecular weight as well as with the relative content of each comonomer in the copolymers and the amount of HDI in the poly(ester-urethane) was analysed. The results obtained demonstrate that these bio tri-block copolymers and the corresponding poly(ester-urethane)s can be tailored with interesting crystalline and mechanical properties. Future applications as shape memory systems are thus envisaged.

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“…[1][2][3][4][5][6][7][8][9] Among aliphatic biodegradable polyesters, poly(butylene succinate) (PBS) is considered to be a promising material in many fields because it has excellent biodegradability, melt processibility and chemical resistance. However, PBS has limited applications because of its poor thermal stability and mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

The synthesis of copolymers, blends and composites based on poly(butylene succinate)

Hwang

Yoo

2012

Polym J

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Poly(butylene succinate) (PBS) is one of the most available environmentally degradable polymers used in industrial applications. Biodegradable polyesters including PBS have low thermal stability, poor mechanical properties and slow crystallization rates. For this reason, many researchers have investigated PBS composites, especially nanocomposites with functional inorganic materials, to identify other advanced properties. We used two inorganic materials to investigate how nanoparticles could be dispersed in a PBS matrix and to identify the properties that could be advanced by fabricating well-dispersed PBS nanocomposites. Clay and zeolite were used for the nano components because they are well known and widely used inorganic materials in polymer-inorganic nanocomposites. The most challenging problem when fabricating the clay-polymer nanocomposite has been how to separate the clay layers in the composite to overcome the very strong cohesive energies between the clay layers. Numerous studies have introduced modifiers into silicate layers to increase the basal space and facilitate easier polymer chain incorporation. We introduce a urethane group on a clay surface to develop physically enhanced PBS/montmorillonite (MMT) nanocomposites. A series of PBS-based ionomers are synthesized by two-step polycondensation. This study focuses on the effect of the ionic group on dynamic mechanical properties, melt rheology, crystallization behavior and enzymatic hydrolysis. INTRODUCTIONThere has been considerable interest in aliphatic biodegradable polyesters over the last decade because of increased concerns about environmental conservation. 1-9 Among aliphatic biodegradable polyesters, poly(butylene succinate) (PBS) is considered to be a promising material in many fields because it has excellent biodegradability, melt processibility and chemical resistance. However, PBS has limited applications because of its poor thermal stability and mechanical properties.PBS/inorganic nanocomposites have been proposed to overcome these drawbacks, and are being developed as the next generation of biodegradable materials. Numerous studies of clay-based biodegradable polymer nanocomposites have focused on changes in preparation methods and morphological properties, as well as the enhancement of mechanical and thermal properties. 10,11 Ray et al. 10 investigated the degree of exfoliation of PBS/clay nanocomposites with various clay types and demonstrated control of the flocculation of dispersed silicate layers in PBS/clay nanocomposites. The achievement of a fine dispersion of the nanofiller in a polymer matrix is a key problem when attempting to produce biodegradable polymer/clay nanocomposites. As noted above, homogeneous clay dispersions in biodegradable polymer matrix are difficult to achieve because of the strong tendency of clay particles to agglomerate. In previous studies, biodegradable polymer nanocomposites with fully dispersed clay were obtained only when the following factors were considered:

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Synthesis, Solid-State Structure, and Surface Properties of End-Capped Poly(l-lactide)

Cited by 28 publications

References 30 publications

Effect of the molecular weight on the crystallinity of PCL-b-PLLA di-block copolymers

Effect of the molecular weight on the crystallinity of PCL-b-PLLA di-block copolymers

Synthesis of PLLA-b-PCL-b-PLLA linear tri-block copolymers and their corresponding poly(ester-urethane)s: effect of the molecular weight on their crystallisation and mechanical properties

The synthesis of copolymers, blends and composites based on poly(butylene succinate)

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