Crystallization modification of poly(lactide) by using nucleating agents and stereocomplexation

Jiang, Long; Shen, Tianfeng; Xu, Pengwu; Zhao, Xiuying; Li, Xiaojie; Dong, Weifu; Ma, Piming; Chen, Mingqing

doi:10.1515/epoly-2015-0179

Cited by 71 publications

(41 citation statements)

References 105 publications

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“…Despite having desired properties, applications of PLA are stymied by its poor crystallization rate, low crystallinity, low heat distortion temperature (HDT) and relatively high cost. Due to its slow crystallization, PLA products prepared via practical processing methods such as injection molding and extrusion exhibit poor mechanical strength and stiffness above its glass transition (T g ~60°C) (68)(69)(70). Thus, it is necessary to improve the crystallization kinetics of PLA for its practical use.…”

Section: Type Of Application Productsmentioning

confidence: 99%

“…Thus, it is necessary to improve the crystallization kinetics of PLA for its practical use. In fact, several methods such as blending (71,72), adding nucleating agents (73,74), chemical modification (68) and/or adding plasticizing agents (75) have been employed to improve the crystallization kinetics of PLA (69). Addition of nucleating agents enhances crystallization temperature and degree of crystallinity.…”

Section: Type Of Application Productsmentioning

confidence: 99%

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A glimpse of biodegradable polymers and their biomedical applications

Shah

Vasava

2019

E-Polymers

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Over the past two decades, biodegradable polymers (BPs) have been widely used in biomedical applications such as drug carrier, gene delivery, tissue engineering, diagnosis, medical devices, and antibacterial/antifouling biomaterials. This can be attributed to numerous factors such as chemical, mechanical and physiochemical properties of BPs, their improved processibility, functionality and sensitivity towards stimuli. The present review intended to highlight main results of research on advances and improvements in terms of synthesis, physical properties, stimuli response, and/or applicability of biodegradable plastics (BPs) during last two decades, and its biomedical applications. Recent literature relevant to this study has been cited and their developing trends and challenges of BPs have also been discussed.

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Section: Type Of Application Productsmentioning

confidence: 99%

Section: Type Of Application Productsmentioning

confidence: 99%

A glimpse of biodegradable polymers and their biomedical applications

Shah

Vasava

2019

E-Polymers

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“…The ratios of PLLAG to PDLAG and glucose content in feeding had significant impacts on stereocomplex properties. These modifications of PLA are conducive to the performance improvement of PLA materials, which is one focus of contemporary green chemistry [31,32].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Stereocomplex of Poly(lactic acid) and Its Amphiphilic Copolymers Containing Glucose Groups

Zhu

Cao

et al. 2020

Polymers

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The stereocomplex of poly(lactic acid) containing glucose groups (sc-PLAG) was prepared by solution blending from equal amounts of poly(l-lactic acid) (PLLA) and poly(d-lactic acid-co-glucose) (PDLAG), which were synthesized from l- and d-lactic acid and glucose by melt polycondensation. The methods, including 1H nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), polarizing microscope (POM), scanning electron microscope (SEM), transmission electron microscope (TEM), and contact angle were used to determine the effects of the stereocomplexation of enantiomeric poly(lactic acid) (PLA) units, the amphiphilicity due to glucose residues and lactic acid units, and the interaction of glucose residues with lactic units on the crystallization performance, hydrophilicity, thermal stability, and morphology of samples. The results showed PDLAG was multi-armed, and partial OH groups of glucose residues in PDLAG might remain unreacted. The molecular weight (Mw), dispersity (Ɖ), and glucose proportion in the chain of PDLAG thereby had significant effects on sc-PLAG. There were the stereocomplexation of enantiomeric lactic units and the amphiphilic self-assembly of PDLAG in sc-PLAG, which resulted in glucose groups mainly in the surface phase and lactic units in the bulk phase. The sc-PLAG only possessed the stereocomplex crystal owing to the interaction between nearly equimolar of l-lactic units of PLLA and d-lactic units of PDLAG, and had no homo-crystallites of l- or d-lactic units, which improved the melting temperature (Tm) of sc-PLAG about 50 °C higher than that of PLLA. Glucose groups in sc-PLAG played an important role by forming heterogeneous nucleation, promoting amphiphilic self-assembly, and affecting the ordered arrangement of lactic units. The glass transition temperature (Tg), the melting temperature (Tm), crystallinity, crystallization rate, and water absorption of sc-PLAG showed similar changes with the increased glucose content in feeding. All these parameters increased at first, and the maximum appeared as glucose content in feeding about 2%, such as the maximum crystallinity of 48.8% and the maximum water absorption ratio being 11.7%. When glucose content in feeding continued increasing, all these performances showed a downward trend due to the decrease of arrangement regularity of lactic acid chains caused by glucose groups. Moreover, the contact angle of sc-PLAG decreased gradually with the increased glucose content in feeding to obtain the minimum 77.5° as the glucose content in feeding being 5%, while that of PLLA was 85.0°. The sc-PLAG possessed a regular microsphere structure, and its microspheres with a diameter of about 200 nm could be observed. In conclusion, sc-PLAG containing proper glucose amount could effectively enhance the crystallinity, hydrophilicity, and thermal stability of PLA material, which is useful for drug delivery, a scaffold for tissue engineering, and other applications of biomedicine.

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“…Inorganic agents are usually called physical nucleating agents. For consideration of the relative large specific surface area of nano‐sized particles, many traditional inorganic particles were refined into nano‐size and then used as nucleating agents in PLLA, such as nano‐sized talc, MMT, and CaCO 3 ; however even some nano‐scaled clays, carbon nanotubes (CNT) and graphene oxide (GO) were also selected as nucleating agents in PLLA. While interesting, this approach is limited in that poor compatibilities between the inorganic nano‐sized particles and the PLLA polymer base have been reported to lead to agglomeration of nano‐sized inorganic particles, resulting in decrease on both nucleation efficiency and mechanical performance.…”

Section: Introductionmentioning

confidence: 99%

Effects of divinylbenzene‐maleic anhydride copolymer hollow microspheres on crystallization behaviors, mechanical properties and heat resistance of poly(l‐lactide acid)

Qiao

Wang

et al. 2019

Polymers for Advanced Techs

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Divinylbenzene‐maleic anhydride copolymer hollow microspheres (DMs) were used as novel organic nucleating agents to promote crystallization of poly(l‐lactide acid) (PLLA). The effects of these DMs on crystal behaviors of the PLLA were investigated by differential scanning calorimeter (DSC), polarizing optical microscopy (POM), and wide angle X‐ray diffraction (WAXD). Both isothermal and non‐isothermal processes in DSC demonstrated that the DMs significantly altered the crystal behaviors of PLLA as both crystallization velocity and degree of crystallinity increased with increasing DM loadings from 0 to 3%. Our POM results also indicated that as nucleating agents, the DMs promoted nucleating densities and decreased spherulitic sizes. In addition, WAXD suggeted that the addition of DMs did not induce new types of crystals. Finally, our results showed that the ductility of the PLLA was enhanced by a small amount of DMs during the PLLA crystallization process since 0.5% DMs added to the PLLA resulted in 1.4‐fold increase in the elongation at break in comparision with the neat PLLA.

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Crystallization modification of poly(lactide) by using nucleating agents and stereocomplexation

Cited by 71 publications

References 105 publications

A glimpse of biodegradable polymers and their biomedical applications

A glimpse of biodegradable polymers and their biomedical applications

Preparation and Properties of Stereocomplex of Poly(lactic acid) and Its Amphiphilic Copolymers Containing Glucose Groups

Effects of divinylbenzene‐maleic anhydride copolymer hollow microspheres on crystallization behaviors, mechanical properties and heat resistance of poly(l‐lactide acid)

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