The physical properties of poly(l-lactide) and functionalized eggshell powder composites

Abstract

Aiming at improved crystallization performance and simultaneously enhanced solid-state properties of poly(l-lactide) such as mechanical properties and enzymatic hydrolysis. A novel functionalized eggshell powder decorated with calcium phenylphosphonic acid (NES) was synthesized via the chemical reaction between phenylphosphonic acid and calcium ion on the surface of eggshell powder to form effective nucleating surface for poly(l-lactide). The resultant NES was incorporated into PLLA matrix to form fully biodegradable composites by melt blending, which exhibited superior crystallization, mechanical properties, and enzymatic hydrolysis. Upon the addition of 20 wt% NES, the crystallization half-time of a PLLA/NES composite decreased from 27.09 to 0.69 min at 130°C, compared to that of neat PLLA. The storage and tensile moduli of the composites increased with increasing NES loadings. Even with 20 wt% NES, the composite still exhibited good mechanical properties with tensile strength of 53.4 MPa, tensile modulus of 2460MPa and elongation at break of 2.5%, respectively. Moreover, it was interesting to find that the enzymatic hydrolytic degradation rates had been enhanced pronouncedly in the PLLA/NES composites than in neat PLLA. Such high performance biocomposites have great potential in expanding the utilization of eggshell powder from sustainable resources and practical application as PLLA-based bioplastic.

A critical review on erosion wear characteristics of polymer matrix composites

“…Researchers YiLi et al [98], Anil et al [99], Bootklad and Kaewtatip [100] have also reported the egg shell particulate PMCs.…”

Structure variation and properties enhancement of uniaxial stretching poly(l‐lactic acid)/eggshell powder composites

“…47 The significant increased T g can enhance the heat resistance of PLLA composites, which will expand the applications of PLLA. In a previous paper, 19 we measured the elastic modulus of unstretched PLLA/ES composites containing 10 wt % ES to be only 3022 MPa at 20 C. These results reveal the enhancement of mechanical properties is mainly due to the improvement of PLLA crystallization by uniaxial stretching, rather than reinforcement by adding ES particles. As shown, E 0 hardly changes below T g and starts to drop near T g .…”

“…Figure 7(b) illustrates the temperature dependence of elastic modulus (E 0 ) of unstretched PLLA and stretched composites with a stretch ratio of 6. At 80 C, the modulus of unstretched PLLA, PLLA90/ES10 composite, 19 and stretched PLLA90/ES10 composites with stretch ratios of 6 are 4, 9, and 590 MPa, respectively. Moreover, the stretched PLLA/ES composites show much less decrease and higher E 0 than that of unstretched PLLA.…”

“…7 Overcoming these problems by means of compounding with fillers or blending with compatible polymers has been an active research area. 10 It can be seen from the existing literature that many kinds of fillers, such as talc, 11 carbon nanotubes, 12,13 montmorillonite, 14 stereocomplex polylactide, 15 silicon dioxide, 16 starch, 17,18 and eggshell (ES) powder, 19,20 and so forth, have been introduced into PLLA in order to enhance strength and/or increase crystallization rate. 10 It can be seen from the existing literature that many kinds of fillers, such as talc, 11 carbon nanotubes, 12,13 montmorillonite, 14 stereocomplex polylactide, 15 silicon dioxide, 16 starch, 17,18 and eggshell (ES) powder, 19,20 and so forth, have been introduced into PLLA in order to enhance strength and/or increase crystallization rate.…”

Composite Superabsorbent Hydrogel of Acrylic Copolymer and Eggshell: Effect of Biofiller Addition

“…Eggshell (ES) is composed mainly of calcium carbonate, and thus its addition to hydrogels should provide an increase in water absorption. 11 A comparison between the effects of eggshell and dolomite on the swelling of superabsorbents can be correlated with the effects of calcium carbonate or magnesium carbonate. In addition, the use of eggshell provides an important environmental benefit, reducing the level of a waste material to be discarded by processing it into a useful product.…”