Influence of clay content on the melting behavior and crystal structure of nonisothermal crystallized poly(L‐lactic acid)/nanocomposites

Abstract

To study the effect of organophilic clay concentration on nonisothermal crystallization, poly(L-lactic acid) (PLLA)/montmorillonite (MMT) nanocomposites were prepared by mixing various amounts of commercial MMT (Cloisite V R 30B) and PLLA. The effect of MMT content on melting behavior and crystal structure of nonisothermal crystallized PLLA/MMT nanocomposites was investigated by differential scanning calorimetry (DSC), small-angle Xray scattering, and wide-angle X-ray diffraction (XRD) analyses. The study was focused on the effect of the filler concentration on thermal and structural properties of the nonisothermally crystallized nanocomposite PLLA/MMT.The results obtained have shown that at filler loadings higher than 3 wt %, intercalation of the clay is observed. At lower clay concentrations (1-3 wt %), exfoliation predominates. DSC and XRD analysis data show that the crystallinity of PLLA/MMT composites increases drastically at high clay loadings (5-9 wt %). In these nanocomposites, PLLA crystallizes nonisothermally in an orthorhombic crystal structure, assigned to the a form of PLLA.

Pressure-Sensitive Touch Panel Based on Piezoelectric Poly(L-lactic acid) Film

“…PLLA does not exhibit pyroelectricity because it does not have an intrinsic polarization. [16][17][18][19][20][21][22] PVDF is a polymer that belongs to the ferroelectric group, and exhibits pyroelectricity because it has an intrinsic polarization. Figure 2 shows the time dependence of the amount of electric charge generated in PLLA and PVDF films due to heat.…”

Isothermal crystallization kinetics and melting behavior of poly(l-lactic acid)/WS2 inorganic nanotube nanocomposites

“…Effective nucleating agents reported for PLLA are zinc phenylphosphonate (PPZn) [9] and p-tert-butylcalix [8] arene [10], talc [11], uracil [12] and N,N 0 -bis(benzoyl) suberic acid dihydrazide [13], whilst cellulose nanocrystals (CNC) [14], titanium dioxide (TiO 2 ) nanowires [15], polyhedral oligomeric silsesquioxanes (POSS) [16,17], nanclay (MMT) [18], carbon nanotubes (CNTs) [19], nanocalcium carbonate (CaCO 3 ) [20], nano-zinc citrate (ZnCC) [21], graphene oxide (GO) [22] and fullerenes (C60) [23], are known as nanocomposite-forming additives. However, the fabrication of high quality nanocomposites normally requires chemical treatment to reduce the surface energy in order to ensure good particle dispersion and strong interaction and adhesion between the nanofiller and polymer matrix.…”

The influence of the preparation conditions and filler content on thermal properties of poly-l -lactide and hydroxyapatite/poly-l -lactide nanocomposite

“…Despite the fact that there are a few reports dealing with the influence of filler content or preparation conditions on the properties of PLLA and its nanocomposites, data on the joint effects of these factors on composites based on PLLA and calcium phosphate ceramics intended for use in orthopedic applications are quite limited . Therefore, the intention of this work was to give a wide and complex depiction regarding the combined influence of the initial preparation conditions and filler content on the structure, crystallinity and thermal properties of PLLA and HAp/PLLA nanocomposites.…”