Preparation and Characterization of Pure PVA and PVA/MMT Matrix: Effect of Thermal Treatment

Authors: Albana Hasimi, Edlira Tako, Partizan Malkaj, Elvin Çomo, Blerina Papajani, Mirela Ndrita, Ledjan Malaj

Abstract:

Many endeavors have been exerted during the last years for developing new artificial polymeric membranes, which fulfill the demanded conditions for biomedical uses. One of the most tested polymers is Poly(vinyl alcohol) [PVA]. Our teams are based on the possibility of using PVA for personal protective equipment against COVID-19. In personal protective equipment, we explore the possibility of modifying the properties of the polymer by adding Montmorillonite [MMT]. Heat-treatment above the glass transition temperature is used to improve mechanical properties mainly by increasing the crystallinity of the polymer, which acts as a physical network. Temperature-Modulated Differential Scanning Calorimetry (TMDSC) measurements indicated that the presence of 0.5% MMT in PVA causes a higher Tg value and shaped peak of crystallinity. Decomposition is observed at two of the melting points of the crystals during heating 25-240 oC and overlap of the recrystallization ridges during cooling 240-25 oC. This is indicative of the presence of two types (quality or structure) of polymer crystals. On the other hand, some indication of improvement of the quality of the crystals by heat-treatment is given by the distinct non-reversing contribution to melting. Data on sorption and transport of water in PVA films: PVA pure and PVA/MMT matrix, modified by thermal treatment are presented. The membranes become more rigid as a result of the heat treatment and because of this the water uptake is significantly lower in membranes. That is indicated by analysis of the resulting water uptake kinetics. The presence of 0.5% w/w of MMT has no significant impact on the properties of PVA membranes. Water uptake kinetics deviate from Fick’s law due to slow relaxation of glassy polymer matrix for all types of membranes.

Keywords: Crystallinity, montmorillonite, nanocomposite, poly(vinyl alcohol).

References:

[1] Vincent Chi-Chung Cheng et al., 2020; The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2 Journal of Infection Volume 81, Issue 1, Pages 107-114. July 2020.
[2] Elbadawy A Kamoun, El-Refaie S Kenawy, Xin Chen. A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings Journal of Advanced Research Volume 8, Issue 3, Pages 217-233, May 2017.
[3] Aditya Sood, Mark S Granick, Nancy L Tomaselli, Wound dressings and comparative effectiveness data. Adv Wound Care 2014;3 (8):511–29.
[4] Mirela Teodorescu, Simona Morariu. Drug delivery system based on PVA and clay for potential treatment of COVID‑19 Journal of Polymer Research (2022) 29: 67.
[5] Vahid Babaahmadi, Hooman Amid, Mohammadreza Naeimirad, Seeram Ramakrishnac. Biodegradable and multifunctional surgical face masks: A brief review on demands during COVID-19 pandemic, recent developments, and future perspectives. Science of the Total Environment 798 (2021) 149233.
[6] Chun Fah Mok, Yern Chee Ching, Farina Muhamad, Noor Azuan Abu Osman, Nguyen Dai Hai & Che Rosmani Che Hassan. Adsorption of Dyes Using Poly(vinyl alcohol) (PVA) and PVA-Based Polymer Composite Adsorbents: A Review. J Polym Environ 28, 775–793, 2020.
[7] Yan Li, Huafeng Tian, Qingqing Jia, Ping Niu, Aimin Xiang, Di Liu, Yanan Qin, Development of polyvinyl alcohol/intercalated MMT composite foams fabricated by melt extrusion J. Appl. Polym. Sci. 2015, 132, 42706.
[8] A. Hasimi, A. Stavropoulou, K.G. Papadokostaki, M. Sanopoulou, Transport of water in polyvinyl alcohol films: Effect of thermal treatment and chemical crosslinking European Polymer Journal 2008 V44/12, Pages 4098-4107
[9] Uddin F (2018) Montmorillonite: An Introduction to Properties and Utilization. Current Topics in the Utilization of Clay in Industrial and Medical Applications. InTech. DOI: 10.5772/intechopen.77987.
[10] Edlira TAKO, Altin MELE, Fatmir SHEHU, ″Identifying Clay Swelling Pattern″, InternationalJournal of Ecosystems and Ecology Science Volume 4/4, 2014, page 627-632.
[11] Hickey AS, Peppas NA. Mesh size and diffusive characteristics of semi-crystalline poly(vinyl alcohol) membranes prepared by freezing/thawing techniques. J Membrane Sci 1995;107:229–37.
[12] Stavropoulou A, Papadokostaki KG, Sanopoulou M. Experimental and theoretical study of the release kinetics of propranolol hydrochloride from PVA matrices. J Controlled Rel 2005;101:313–5.
[13] Wang H-L, Fernandez JE. Blends of polypyrrole and poly(vinyl alcohol). Macromolecules 1993;26:3336–9.
[14] Herman S. MansuR, Carolina M. Sadahira, Adriana N. Souza, Alexandra A.P. Mansur. FTIR spectroscopy characterization of poly (vinyl alcohol) hydrogel with different hydrolysis degree and chemically crosslinked with glutaraldehyde. Materials Science and Engineering C 28 p. 539–548, 2008.
[15] N.A. Peppas, Hydrogels in Medicine and Pharmacy 2, CRC Press, Florida,1986.
[16] S.K. Mallapragada, N.A. Peppas, P. Colombo, Journal of Biomedical Materials Research 36 (1996) 125.