scholarly journals Lamellae Evolution of Stereocomplex-Type Poly(Lactic Acid)/Organically-Modified Layered Zinc Phenylphosphonate Nanocomposites Induced by Isothermal Crystallization

Materials ◽  
2016 ◽  
Vol 9 (3) ◽  
pp. 159 ◽  
Author(s):  
Yi-An Chen ◽  
Erh-Chiang Chen ◽  
Tzong-Ming Wu
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Poly Lactic Acid ◽  
Organically Modified

Dispersion of Organically Modified Layered Silicates in Melt Blended Poly(Lactic Acid) Composites: Effects of Cation Head Groups and Oxygenated Alkyl Chains

2013 ◽  
Vol 50 (11) ◽  
pp. 665-675
Author(s):  
D. M. Fox ◽  
M. Zammarano ◽  
M. Novy ◽  
L. M. Haverhals ◽  
H. De Long ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Layered Silicates ◽  
Poly Lactic Acid ◽  
Alkyl Chains ◽  
Head Groups ◽  
Organically Modified

scholarly journals Composites Based on Poly(Lactic Acid) (PLA) and SBA-15: Effect of Mesoporous Silica on Thermal Stability and on Isothermal Crystallization from Either Glass or Molten State

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2743
Author(s):  
Tamara M. Díez-Rodríguez ◽  
Enrique Blázquez-Blázquez ◽  
Ernesto Pérez ◽  
María L. Cerrada
Keyword(s):  
Lactic Acid ◽  
Mesoporous Silica ◽  
Isothermal Crystallization ◽  
Physical Aging ◽  
Glassy State ◽  
Poly Lactic Acid ◽  
Molten State ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Several composites based on an L-rich poly(lactic acid) (PLA) with different contents of mesoporous Santa Barbara Amorphous (SBA-15) silica were prepared in order to evaluate the effect of the mesoporous silica on the resultant PLA materials by examining morphological aspects, changes in PLA phases and their transitions, and, primarily, the influence on some final properties. Melt extrusion was chosen for the obtainment of the composites, followed by quenching from the melt to prepare films. Completely amorphous samples were then attained, as deduced from X-ray diffraction and differential scanning calorimetry (DSC) analyses. Thermogravimetric analysis (TGA) results demonstrated that the presence of SBA-15 particles in the PLA matrix did not exert any significant influence on the thermal decomposition of these composites. An important nucleation effect of the silica was found in PLA, especially under isothermal crystallization either from the melt or from its glassy state. As expected, isothermal crystallization from the glass was considerably faster than from the molten state, and these high differences were also responsible for a more considerable nucleating role of SBA-15 when crystallizing from the melt. It is remarkable that the PLA under analysis showed very close temperatures for cold crystallization and its subsequent melting. Moreover, the type of developed polymorphs did not accomplish the common rules previously described in the literature. Thus, all the isothermal experiments led to exclusive formation of the α modification, and the observation of the α’ crystals required the annealing for long times at temperatures below 80 °C, as ascertained by both DSC and X-ray diffraction experiments. Finally, microhardness (MH) measurements indicated a competition between the PLA physical aging and the silica reinforcement effect in the as-processed amorphous films. Physical aging in the neat PLA was much more important than in the PLA matrix that constituted the composites. Accordingly, the MH trend with SBA-15 content was strongly dependent on aging times.

Non-isothermal crystallization kinetics, thermal degradation behavior and mechanical properties of poly(lactic acid)/MOF composites prepared by melt-blending methods

RSC Advances ◽  
2016 ◽  
Vol 6 (75) ◽  
pp. 71461-71471 ◽  
Author(s):  
Xiu Dai ◽  
Yu Cao ◽  
Xiaowei Shi ◽  
Xinlong Wang
Keyword(s):  
Lactic Acid ◽  
Thermal Degradation ◽  
Isothermal Crystallization ◽  
Metal Organic Framework ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Isothermal Crystallization Kinetics ◽  
Blending Method ◽  
Thermal Degradation Behavior ◽  
Metal Organic

In this article, poly(lactic acid)/metal–organic framework composites were prepared by melt-blending method and the effects of MOFs on the non-isothermal crystallization, thermal degradation and mechanical property of poly(lactic acid) were studied.

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