Phase Morphology, Mechanical, and Thermal Properties of Calcium Carbonate-Reinforced Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastics

Abstract

Poly(L-lactide) (PLLA) is a promising candidate as a bioplastic because of its non-toxicity and biodegradability. However, the low flexibility of PLLA limits its use in many applications. Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-b-PEG-b-PLLA) block copolymer is of interest for bioplastic applications due to its superior flexibility compared to PLLA. The aim of this work is to modify PLLA-b-PEG-b-PLLA using a low-cost calcium carbonate (CaCO3) filler to improve material properties compared to PLLA/CaCO3 composites. The addition of CaCO3 enhanced the crystallinity and thermal stability for the PLLA-b-PEG-b-PLLA matrix but not for the PLLA matrix, as determined by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA). Phase morphology investigation using scanning electron microscopy (SEM) revealed that the interfacial adhesion between PLLA-b-PEG-b-PLLA and CaCO3 was stronger than between PLLA and CaCO3. Additionally, tensile testing was carried out to determine the mechanical properties of the composites. With the addition of CaCO3, the tensile stress and Young’s modulus of the PLLA-b-PEG-b-PLLA matrix were increased, whereas these properties of the PLLA matrix were significantly decreased. Thus, CaCO3 shows great promise as an inexpensive filler that can induce nucleation and reinforcing effects for PLLA-b-PEG-b-PLLA bioplastics.

The permeability of diamond and other microphase-separated morphologies in copolymer films

“…In the weak segregation approximation, the order parameter can be expanded in terms of the main Fourier harmonics 23 CðrÞ ¼ X q2M C q expðiqrÞ; (10) where C q is an amplitude and M is a set of main harmonics that determine the system topology. Additionally, the system is supposed to be incompressible, i.e., the sum of the order parameters for all its components is zero.…”

“…Thus, the percolation contrast values found within the SCFT framework are close to upper boundary j a 2 þ ffiffi ffi 2 p À Á =4 % 0:85 evaluated for the DM morphology in the weak segregation approximation, and even slightly exceed it. This excess can be explained by the effect of the surface pattern (28) and also by the presence of higher harmonics in the expansion of order parameter (10), in addition to the main harmonics. It is also worth noticing that the curve of the maximum volume fraction of A component for the D 2 phase in Fig.…”

“…5,6 One of the areas of practical use of block copolymers is the production of isoporous membranes for filtration of liquids and ion transport. [7][8][9][10][11][12][13] Compared to solid porous bodies with a substance or void (pore) at any point under consideration, soft matter, which includes polymers, is characterized by the interpenetration of its constituent components into each other. To describe their distribution, local characteristics are used, for example, concentration (or volume fraction) as a function of a point in space.…”

Polyacrylonitrile-containing amphiphilic block copolymers: self-assembly and porous membrane formation

“…Many more BCPs have been used to fabricate SNIPS membranes based on the deepened knowledge in the following years. 5,19,21 For example, the introduction of PHEMA as hydrophilic block bearing accessible hydroxy-moieties by Schöttner et al 22 paved the way to multiple post-modification possibilites. [23][24][25][26] The formation of a membrane via the SNIPS process includes three essential steps: preparing a semi-concentrated solution of the BCP in a solvent mixture, casting the membrane solution by doctor blading and, after an appropriate evaporation time, freezing the membrane in its non-equilibrium state by immersion in a precipitation bath.…”

“…18 Within a recent work, Blagojevic and Müller identified the most important influencing parameters using simulations. 29 Although valuable work has been published in this field, 4,19,21 there is still need for improvement regarding the membranes' mechanical stability. Amongst others, 30 our group has approached this issue by incorporating UV-crosslinkable moieties into a methacrylate-based amphiphilic BCP prepared by ATRP, 31 leading to improved solvent resistance and mechanical stability.…”