scholarly journals Improvement in Crystallizability and Melt Flow Property of Linear Poly(L-lactide) Bioplastic by Blending with Star-shaped Poly(L-lactide)

2018 ◽  
Vol 34 (4) ◽  
pp. 1878-1883 ◽  
Author(s):  
Yodthong Baimar ◽  
Yaowalak Srisuwan
Keyword(s):  
Flow Property ◽  
Nucleating Agent ◽  
Chain Extender ◽  
Chain Extension ◽  
Melt Blending ◽  
Melt Flow ◽  
Blend Ratio ◽  
Melt Strength ◽  
Blend Films ◽  
Linear Poly

This research focuses on the crystallizability and melt flow property of linear poly(L-lactide) (1-PLL) by blending with star-shaped 16-arm PLL (16-PLL). The 1-PLL/16-PLL blends were chain extended during melt blending using an epoxy-based chain extender. The crystallinities of the 1-PLL/16-PLL blends increased with the 16-PLL blend ratio and chain extension reaction. The 16-PLL enhanced formation of branched PLL during chain extension was confirmed by thermogravimetry, and improved the melt flow property of the blends. Stresses at break of the compressed blend films were improved slightly by the 16-PLL blending and chain extension. In conclusion, the 16-PLL could be used as a nucleating agent and a melt strength enhancer for linear PLL.

scholarly journals Toughening of Poly(L-lactide) with Blends of Poly(ε-caprolactone-co-L-lactide) in the Presence of Chain Extender

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Yaowalak Srisuwan ◽  
Yodthong Baimark ◽  
Supakij Suttiruengwong
Keyword(s):  
Impact Strength ◽  
Melt Flow Index ◽  
Chain Extender ◽  
Chain Extension ◽  
Flow Index ◽  
Melt Blending ◽  
Melt Flow ◽  
Phase Compatibility ◽  
The Impact ◽  
Reactive Melt

A poly(ε-caprolactone-co-L-lactide) copolyester was synthesized and employed to toughen poly(L-lactide) (PLLA) by reactive melt blending in the presence of an epoxy-based chain extender. The effects of chain extension reaction and copolyester content on properties of PLLA-based blends were studied. The chain extension reaction reduced crystallinity and melt flow index of PLLA/copolyester blends. Meanwhile the copolyester blending improved the crystallinities of the chain-extended PLLA up to 20 wt% copolyester. The phase compatibility between PLLA matrix and dispersed copolyester phases was enhanced by the chain extension reaction. The impact strength of chain-extended PLLA increased with the contents of copolyester and chain extender.

scholarly journals Preparation of Stereocomplex Polylactide/Poly(Butylene Succinate) Blends by Melt Blending

2019 ◽  
Vol 35 (3) ◽  
pp. 958-965 ◽  
Author(s):  
Jenjira Jirum ◽  
Yodthong Baimark
Keyword(s):  
Amorphous Region ◽  
Chain Extender ◽  
Chain Extension ◽  
Melt Blending ◽  
Butylene Succinate ◽  
Blend Films ◽  
Thermal Phase ◽  
A Chain ◽  
Phase Compatibility ◽  
Thermal Stability Of

Biodegradable polymer blends based on stereocomplex polylactide (scPLA) and poly(butylene succinate) (PBS) were successfully formed by continuous two-step melt blending. An epoxy-based, multifunctional chain extender was chosen to enhance phase compatibility of the blends. Effects of PBS and chain extender on thermal, phase morphology, thermo-mechanical and tensile properties of the scPLA/PBS blends were determined. The PBS blending enhanced plasticizing effect and cold-crystallization of scPLA matrix in an amorphous region. The chain-extension reaction inhibited crystallization of PBS, PLA homo-crystallites and PLA stereocomplex-crystallites as well as reduced thermal stability of the scPLA/PBS blends because of formation of long-chain branched structures. It has been shown that the poor phase compatibility between continuous scPLA and dispersed PBS phases of the blends may be solved through melt blending with a chain extender. The chain extension of scPLA/PBS blends also improved thermo-mechanical properties and flexibility of the scPLA/PBS blend films.

scholarly journals Influence of Chain-Extension Reaction on Stereocomplexation, Mechanical Properties and Heat Resistance of Compressed Stereocomplex-Polylactide Bioplastic Films

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1218 ◽  
Author(s):  
Yodthong Baimark ◽  
Sumet Kittipoom
Keyword(s):  
Mechanical Properties ◽  
Differential Scanning Calorimetry ◽  
Heat Resistance ◽  
Tensile Testing ◽  
Chain Extender ◽  
Chain Extension ◽  
Melt Blending ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Xrd Patterns

Stereocomplex polylactide (scPLA) films were prepared by melt blending of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) with and without an epoxy-based chain extender before compression molding. The obtained scPLA films were characterized through differential scanning calorimetry, X-ray diffractometry (XRD), tensile testing and dimensional stability to heat. XRD patterns revealed that all the scPLA films had only stereocomplex crystallites. The obtained results showed that the chain-extension reaction improved mechanical properties of the scPLA films, however, it suppressed stereocomplexation and heat resistance.

Thermal and mechanical properties of highly flexible poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) bioplastics: Effects of poly(ethylene glycol) block length and chain extender

2019 ◽  
Vol 52 (2) ◽  
pp. 142-158 ◽  
Author(s):  
Yodthong Baimark ◽  
Yaowalak Srisuwan
Keyword(s):  
Ethylene Glycol ◽  
Chain Extender ◽  
Chain Extension ◽  
Block Length ◽  
Melt Blending ◽  
Poly Ethylene Glycol ◽  
Lower Stress ◽  
Practical Applications ◽  
Poly Ethylene ◽  
Reactive Melt

The brittleness of poly(L-lactide) (PLLA) bioplastic is the main disadvantage for practical applications. Herein, we report the synthesis of high-molecular-weight PLLA- b-poly(ethylene glycol)- b-PLLA (PLLA-PEG-PLLA) block copolymers by ring-opening polymerization of LLA. The highly flexible PLLA-PEG-PLLAs were prepared by reactive melt blending with an epoxy-based chain extender formed as long-chain branched structures. The effects of PEG block length and content of chain extender were investigated. The results showed that the chain extension reaction reduced crystallinities of the PLLA-PEG-PLLAs. All the chain-extended PLLA-PEG-PLLA films had no phase separation. The lower crystallinities of PLLA-PEG-PLLA films obtained with higher contents of chain extender enhanced the film drawability. The longer PEG block length resulted in higher strain at break and lower stress at the break of PLLA-PEG-PLLA films. These chain-extended PLLA-PEG-PLLAs have potential for use as highly flexible bioplastics.

scholarly journals Thermal and Mechanical Properties of Biodegradable Star-Shaped/Linear Polylactide Stereocomplexes

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Onanong Cheerarot ◽  
Yodthong Baimark
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Solvent Casting ◽  
Thermal And Mechanical Properties ◽  
Casting Method ◽  
Blend Ratio ◽  
Blend Films ◽  
Molecular Weights ◽  
Linear Poly ◽  
Blend Ratios

The 6-arm star-shaped poly(L-lactide) (6PLL)/linear poly(D-lactide) (1PDL) stereocomplex films were prepared by the solvent casting method. The influences of the 6PLL/1PDL blend ratios (75/25, 50/50, and 25/75 w/w) and 1PDL molecular weights (15,000, 30,000, and 60,000 g/mol) on the thermal and mechanical properties of the stereocomplex films were investigated. The 6PLL and 1PDLs had a single melting temperature (Tm) of homocrystallites at 174°C and 167°C, respectively. The 6PLL/1PDL blends had twoTms: a lowerTmof homocrystallites (160–173°C) and a higherTmof stereocomplex crystallites (219–228°C). The stereocomplex crystallinity and mechanical properties of the 6PLL/1PDL blend films were higher than those of 6PLL and 1PDL and were the highest in the 50/50 (w/w) blend ratio. However, the stereocomplex crystallinity of the 50/50 (w/w) 6PLL/1PDL blend films decreased and the mechanical properties increased as the molecular weight of 1PDL increased.

Isothermal Crystallization Behavior of Poly (L-lactic Acid)/ Surface-Grafted Silica Nanocomposites

2012 ◽  
Vol 268-270 ◽  
pp. 37-40 ◽  
Author(s):  
Yan Hua Cai
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melt Blending ◽  
Scanning Calorimetry ◽  
Silica Nanocomposites ◽  
Induction Periods ◽  
Sio2 Nanocomposites ◽  
Different Content

The Poly(L-lactic acid)(PLLA)/surface-grafting silica(g-SiO2) nanocomposites were prepared by melt blending. The isothermal crystallization behavior of PLLA/g-SiO2 nanocomposites with different content of g-SiO2 was investigated by optical depolarizer. In isothermal crystallization from melt, the induction periods and half times for overall PLLA crystallization (95°C Tc 120°C) were affected by the crystallization temperature and the content of g-SiO2 in nanocomposites. The results showed that g-SiO2 as a kind of heterogeneous nucleating agent can reduce induction periods and half times for overall PLLA crystallization. The thermal properties of PLLA/g-SiO2 samples were also investigated by differential scanning calorimetry (DSC), The results showed that the crystalline degree of PLLA was improved as the presence of g-SiO2.

scholarly journals Effects of chain extender on properties and foaming behavior of polypropylene foam

RSC Advances ◽  
2019 ◽  
Vol 9 (44) ◽  
pp. 25496-25507 ◽  
Author(s):  
Do Young Kim ◽  
Ji Hun Cha ◽  
Kwan Ho Seo
Keyword(s):  
Chain Extender ◽  
Chain Extension ◽  
Foaming Behavior ◽  
Polypropylene Foam

The mechanism of the grafting and chain extension reaction and changes in the PP structure and foamability.

scholarly journals Processing and nanomechanical properties of chitosan/polyethylene oxide blend films

2012 ◽  
Vol 77 (12) ◽  
pp. 1723-1733 ◽  
Author(s):  
Jelena Djokic ◽  
Aleksandar Kojovic ◽  
Dusica Stojanovic ◽  
Aleksandar Marinkovic ◽  
Goran Vukovic ◽  
...  
Keyword(s):  
Polyethylene Oxide ◽  
Manufacturing Cost ◽  
Scanning Calorimetry ◽  
Blend Ratio ◽  
Blend Films ◽  
Nanomechanical Properties ◽  
Mechanical Integrity ◽  
Reduced Modulus ◽  
Optimal Values ◽  
Chitosan Films

Chitosan based films have found an increasing implementation in variety of topics among which as drug delivery carriers, in packaging industry and as water puritication filters. Therefore, in order to achieve mechanical integrity of such films while preserving processability and biocompatibility, chitosan based films are fabricated in forms of blends with polyethylene oxide (PEO). Nanoindentation study is undertaken in order to investigate nanomechanical properties and surface morphology of chitosan films in blends with various content of PEO. Results of differential scanning calorimetry, water uptake and nanoindentation revealed that films with 80/20 blend ratio of chitosan/PEO showed the optimal values of reduced modulus and hardness. It appears that the incorporation of synthetic PEO in chitosan films could lower the manufacturing cost while preserving the mechanical integrity of the films.

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