Stereocomplexation of PLL/PDL–PEG–PDL blends: Effects of blend morphology on film toughness

Tacha, Sunan; Saelee, Tinnakorn; Khotasen, Wootichai; Punyodom, Winita; Molloy, Robert; Worajittiphon, Patnarin; Meepowpan, Puttinan; Manokruang, Kiattikhun

doi:10.1016/j.eurpolymj.2015.06.015

Cited by 20 publications

(11 citation statements)

References 33 publications

(48 reference statements)

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“…38 Fig. 8 Interestingly, for all the copolymers, the transition degradation temperatures were almost independent of the composition. As we could see, all plots demonstrate two glass transition temperatures, indicating the microphase separation.…”

Section: Thermo-mechanical Properties Of Plla-b-pm-b-pllamentioning

confidence: 85%

Fully biobased thermoplastic elastomers: synthesis and characterization of poly(l-lactide)-b-polymyrcene-b-poly(l-lactide) triblock copolymers

et al. 2016

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Graphic AbstractFully biobased thermoplastic elastomers poly(L-lactide)-b-polymyrcene-b-poly(L-lactide) triblock copolymers with PLLA as hard block and polymyrcene as soft block were synthesized and evaluated. † Abstract Fully biobased poly(L-lactide)-b-polymyrcene-b-poly(L-lactide) triblock copolymers with PLLA as the hard block and polymyrcene as the soft block were synthesized by the ring opening polymerization of L-lactide in the presence of dihydroxyl-terminated polymyrcene precursor and organocatalyst. The copolymer composition and molecular weight of these triblock copolymers were confirmed by NMR and GPC results. Two separated glass transition temperatures were detected by both DMA and DSC techniques, indicating an existence of micro-phase separation in these triblock copolymers, which is a typical characteristic of thermoplastic elastomers with the content of soft block increases. Tensile testing revealed that PLLA-b-PM-b-PLLA (200) having 20 wt% polymyrcene show distinct yielding while other samples fracture at low strain without yielding. POM results indicated that all these spherulites show the same characteristic "Maltese cross" patterns. With the increasing content of polymyrcene, the perfection of spherulites decreases, especially for PLLA-b-PM-b-PLLA (200). Considering the current energy and environmental problems, it is expected that these fully biobased thermoplastic elastomers will be of great significance in expanding the applications of PLLA and solving the ecocrisis around us. a Determined by DMA plots Additionally, TGA is operated to investigate the thermostability and the degradation profile of PLLA-b-PM-b-PLLA triblock copolymers. It is well known that the thermal degradation of polymers may involve thermohydrolysis, zipper-like depolymerization, thermo-oxidative degradation, or transesterification reactions. 22 Fig. 4 displays the TGA and DTG curves of these triblock copolymers at a heating rate of 20 o C min -1 under nitrogen atmosphere range from 50 to 600 o C. As shown in Fig.chain segments at glass transition temperatures, respectively. Furthermore, the corresponding loss modulus and tanδ curve are also featured by two separate peaks, the low temperature peak at -40 o C is related to the glass transition of polymyrcene, while the peak at higher temperature, 67 o C, is the glass transition of PLLA segment. 22,39,40 Therefore, microphase separation is further confirmed. For other two copolymers, DMA curves have been shown in the supporting information ( Fig. S3 and Fig. S4).All plots give the similar trends like that demonstrated in Fig. 5, however, the sample was broken

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Section: Thermo-mechanical Properties Of Plla-b-pm-b-pllamentioning

confidence: 85%

Fully biobased thermoplastic elastomers: synthesis and characterization of poly(l-lactide)-b-polymyrcene-b-poly(l-lactide) triblock copolymers

et al. 2016

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“…The block copolymers with relatively low molecular weights can form hydrogels, micelles, nanoparticles, etc., which can be applied to drug control release system . However, the PEG‐PLLA block copolymers which have relatively higher molecular weights can present good mechanical properties and can be used for tissue engineering or as additives (eg, compatibilizer, plasticizer) to enhance the properties of the PLA matrix . In order to make the block copolymer suitable for an application, understanding the crystallization of block copolymers in a wide range would provide an effective method to predict and adjust the performance of the crystallized copolymers.…”

Section: Introductionmentioning

confidence: 99%

The crystallization behavior of poly(ethylene glycol) and poly( l ‐lactide) block copolymer: Effects of block length of poly(ethylene glycol) and poly( l ‐lactide)

Wang

Feng

Shao

et al. 2019

Polymer Crystallization

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A series of poly(ethylene glycol)‐poly(l‐lactide) (PEG‐PLLA) di‐, and tri‐block copolymers that consisted of different lengths of PEG and PLLA blocks were synthesized, and the crystallization behavior of PEG and PLLA blocks were investigated. Results demonstrate that PEG and PLLA blocks interact with each other, and the crystallization and melting behaviors of copolymers are dependent on the composition of PEG and PLLA. The crystallization of PEG block is confined by the existence of PLLA block, the more fraction of PLLA, the greater restriction on PEG. However, this confinement is reduced after PEG with the larger molecular weight is incorporated into the copolymers. The PEG acts as a solvent, which reduces the viscosity and enhances the chain mobility of the PLLA. The melting temperature of PLLA block decreases when the PEG length is increasing or when the molecular weight of PLLA is decreasing. With the increase of the molecular weight of the PLLA block, the crystallinity of PLLA firstly increases and then decreases. For the copolymers with different structures and molecular weights of PEG blocks, the crystallinity and melting point of PLLA block exhibit different unique component dependence.

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“…However the heat-resistance of PLLA-PEG-PLLA was still low. In recent years, PLLA has been blended with PDLA-PEG-PDLA for improving the flexibility of the obtained stereocomplex PLLA/PDLA-PEG-PDLA [14][15][16][17][18][19][20]. Low-molecular-weight PLLA-PEG-PLLA/PDLA-PEG-PDLA blends were prepared as hydrogels [21][22][23][24] and micelles [25,26] for use as drug delivery carriers.…”

Section: Introductionmentioning

confidence: 99%

“…All the high-molecular-weight stereocomplex PLLA/PDLA-PEG-PDLA and PLLA-PEG-PLLA/PDLA-PEG-PDLA were prepared by solution blending [14][15][16][17][18][19][20]27]. However the fabrication of scPLA by melt processing is very interesting because of its possible use in industrial-scale applications.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Mechanical Properties and Heat Resistance of PLLA-b-PEG-b-PLLA by Melt Blending with PDLA-b-PEG-b-PDLA for Potential Use as High-Performance Bioplastics

Pasee

Baimark

2019

Advances in Polymer Technology

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Ecofriendly poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-b-PEG-b-PLLA) are flexible bioplastics. In this work, the blending of poly(D-lactide)-b-poly(ethylene glycol)-b-poly(D-lactide) (PDLA-b-PEG-b-PDLA) with various blend ratios for stereocomplex formation has been proved to be an effective method for improving the mechanical properties and heat resistance of PLLA-b-PEG-b-PLLA films. The PLLA-b-PEG-b-PLLA/PDLA-b-PEG-b-PLDA blend films were prepared by melt blending followed with compression molding. The stereocomplexation of PLLA and PDLA end-blocks were characterized by differential scanning calorimetry and X-ray diffraction (XRD). The content of stereocomplex crystallites of blend films increased with the PDLA-b-PEG-b-PDLA ratio. From XRD, the blend films exhibited only stereocomplex crystallites. The stress and strain at break of blend films obtained from tensile tests were enhanced by melt blending with the PDLA-b-PEG-b-PDLA. The heat resistance of blend films determined from testing of dimensional stability to heat and dynamic mechanical analysis were improved with the PDLA-b-PEG-b-PDLA ratio. The sterecomplex PLLA-b-PEG-b-PLLA/PDL-b-PEG-b-PDLA films prepared by melt processing could be used as flexible and good heat-resistance packaging bioplastics.

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Stereocomplexation of PLL/PDL–PEG–PDL blends: Effects of blend morphology on film toughness

Cited by 20 publications

References 33 publications

Fully biobased thermoplastic elastomers: synthesis and characterization of poly(l-lactide)-b-polymyrcene-b-poly(l-lactide) triblock copolymers

Fully biobased thermoplastic elastomers: synthesis and characterization of poly(l-lactide)-b-polymyrcene-b-poly(l-lactide) triblock copolymers

The crystallization behavior of poly(ethylene glycol) and poly( l ‐lactide) block copolymer: Effects of block length of poly(ethylene glycol) and poly( l ‐lactide)

Improvement in Mechanical Properties and Heat Resistance of PLLA-b-PEG-b-PLLA by Melt Blending with PDLA-b-PEG-b-PDLA for Potential Use as High-Performance Bioplastics

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