Fabrication and Properties of Alkaline Lignin / Poly (Vinyl Alcohol) Blend Membranes

Abstract

Membranes were prepared from alkaline lignin and poly(vinyl alcohol) (PVA) by a film casting method, and their properties were evaluated. These blend membranes can aptly be termed as green by nature as they are totally non-toxic and eco-friendly. The optimal mass ratio was determined based on the mechanical properties of membranes. The microstructure, mechanical properties, oxygen and carbon dioxide transmission, light transmittance, and thermal stability of the membranes were investigated. The blend membrane exhibited better thermal stability and barrier performance to oxygen and carbon dioxide than a PVA membrane due to the incorporation of alkaline lignin. Both tensile strength and elongation at break were increased with increasing mass fraction of alkaline lignin up to 15%, at which point the maximum of tensile strength and elongation at break were 43.65 MPa and 211.6%, respectively. The blockage of visible light at 600 nm was 62.36%, which was an improvement of 314.90% compared with the PVA membrane (13.36%). Based on this result, we suggest that the mechanical properties of blend membrane containing 15% alkaline lignin are excellent and better than PVA membrane (40.26 MPa, 179.37%). Thus, an alkaline lignin/PVA blend membrane was judged to be potentially suitable as an eco-friendly packing material.

Fabrication and Characterization of Lignin Particles and Their Ultraviolet Protection Ability in PVA Composite Film

“…This formation of a new hydrogen bond between the lignin and the polymer matrix has been confirmed by several studies. 40 − 43 The small bands at 2939.92 cm –1 (neat PVA), 2939.60 cm –1 (OL/PVA), and 2939.01 cm –1 (OLPs/PVA) are assigned to the characteristic bands of CH 2 stretching vibration, while 2850.92 cm –1 (neat PVA), 2852.03 cm –1 (OL/PVA), and 2851.42 cm –1 (OLPs/PVA) are related to the stretching vibrations of the C–H. The bands observed at 1086.90 cm –1 (neat PVA), 1087.64 cm –1 (OL/PVA), and 1087.57 cm –1 (OLPs/PVA) were recognized as C–O stretching vibration in which similar results were also reported ( Figure 12 ).…”

Hydrogen bonding interactions in poly(ethylene-co-vinyl alcohol)/lignin blends

“…Poly(vinyl alcohol) contains numerous hydroxyl groups capable of donating hydrogens to the oxygen-containing functional groups of lignin, thus it is expected to be miscible, but at least compatible with lignin. Quite a few studies have been carried out on this combination of materials and most of the authors concluded that they form heterogeneous blends [43,[46][47][48][49], which contradicts the expectations and is quite surprising.…”

“…As described in the introductory part, the opinions on the structure of polymer/lignin blends differ considerably among groups and authors. Miscibility was claimed even for polyolefin/lignin blends [50], while heterogeneous structure was found for example for the PVOH/lignin pair [46][47][48][49]…”

Competitive Interactions in Aromatic Polymer/Lignosulfonate Blends

“…The importance of hydrogen bonds was pointed out in several publications by a number of authors. They were thought to be significant in poly(vinyl chloride) [31,33], poly(vinyl alcohol) [34,35], poly(lactic acid) [37][38][39], and polyhydroxybutyrate [42,43]. In spite of the importance of hydrogens bonds, Doherty et al [54] claimed that they alone are not sufficient to compete successfully with the strong interactions among lignin molecules and to result in complete miscibility.…”

“…A considerable number of papers have been published on the blends of lignin with a wide range of polymers including proteins [10][11][12], starch [13][14][15], polyolefins [16][17][18][19][20][21][22][23][24][25][26], vinyl polymers 4 [18,19,21,[27][28][29][30][31][32][33][34][35] and polyesters [19,21,22,[36][37][38][39][40][41][42][43]. The chemical modification of lignin [10,14,16,[20][21][22]27,29,36,40,…”