Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films
In the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation...
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doaj-d8668bc93b9748da9767c04ef5bb602b2021-09-25T23:39:51ZengMDPI AGApplied Sciences2076-34172021-09-01118433843310.3390/app11188433Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch FilmsPedro A. V. Freitas0Carla I. La Fuente Arias1Sergio Torres-Giner2Chelo González-Martínez3Amparo Chiralt4Research Institute of Food Engineering for Development (IIAD), Universtitat Politècnica de València (UPV), 46022 Valencia, SpainResearch Institute of Food Engineering for Development (IIAD), Universtitat Politècnica de València (UPV), 46022 Valencia, SpainResearch Institute of Food Engineering for Development (IIAD), Universtitat Politècnica de València (UPV), 46022 Valencia, SpainResearch Institute of Food Engineering for Development (IIAD), Universtitat Politècnica de València (UPV), 46022 Valencia, SpainResearch Institute of Food Engineering for Development (IIAD), Universtitat Politècnica de València (UPV), 46022 Valencia, SpainIn the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation of the fibers gave rise to CMFs with cumulative frequencies of length and diameters below 200 and 5–15 µm, respectively. The resultant CMFs were successfully incorporated at, 1, 3, and 5 wt% into TPS by melt mixing and also starch was subjected to dry heating (DH) modification to yield TPS modified by dry heating (TPSDH). The resultant materials were finally shaped into films by thermo-compression and characterized. It was observed that both DH modification and fiber incorporation at 3 and 5 wt% loadings interfered with the starch gelatinization, leading to non-gelatinized starch granules in the biopolymer matrix. Thermo-compressed films prepared with both types of starches and reinforced with 3 wt% CMFs were more rigid (percentage increases of ~215% for TPS and ~207% for the TPSDH), more resistant to break (~100% for TPS and ~60% for TPSDH), but also less extensible (~53% for TPS and ~78% for TPSDH). The incorporation of CMFs into the TPS matrix at the highest contents also promoted a decrease in water vapor (~15%) and oxygen permeabilities (~30%). Finally, all the TPS composite films showed low changes in terms of optical properties and equilibrium moisture, being less soluble in water than the TPSDH films.https://www.mdpi.com/2076-3417/11/18/8433waste valorizationrice strawthermoplastic starchcellulosethermal modificationmicrocomposites |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Pedro A. V. Freitas Carla I. La Fuente Arias Sergio Torres-Giner Chelo González-Martínez Amparo Chiralt |
spellingShingle |
Pedro A. V. Freitas Carla I. La Fuente Arias Sergio Torres-Giner Chelo González-Martínez Amparo Chiralt Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films Applied Sciences waste valorization rice straw thermoplastic starch cellulose thermal modification microcomposites |
author_facet |
Pedro A. V. Freitas Carla I. La Fuente Arias Sergio Torres-Giner Chelo González-Martínez Amparo Chiralt |
author_sort |
Pedro A. V. Freitas |
title |
Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films |
title_short |
Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films |
title_full |
Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films |
title_fullStr |
Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films |
title_full_unstemmed |
Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films |
title_sort |
valorization of rice straw into cellulose microfibers for the reinforcement of thermoplastic corn starch films |
publisher |
MDPI AG |
series |
Applied Sciences |
issn |
2076-3417 |
publishDate |
2021-09-01 |
description |
In the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation of the fibers gave rise to CMFs with cumulative frequencies of length and diameters below 200 and 5–15 µm, respectively. The resultant CMFs were successfully incorporated at, 1, 3, and 5 wt% into TPS by melt mixing and also starch was subjected to dry heating (DH) modification to yield TPS modified by dry heating (TPSDH). The resultant materials were finally shaped into films by thermo-compression and characterized. It was observed that both DH modification and fiber incorporation at 3 and 5 wt% loadings interfered with the starch gelatinization, leading to non-gelatinized starch granules in the biopolymer matrix. Thermo-compressed films prepared with both types of starches and reinforced with 3 wt% CMFs were more rigid (percentage increases of ~215% for TPS and ~207% for the TPSDH), more resistant to break (~100% for TPS and ~60% for TPSDH), but also less extensible (~53% for TPS and ~78% for TPSDH). The incorporation of CMFs into the TPS matrix at the highest contents also promoted a decrease in water vapor (~15%) and oxygen permeabilities (~30%). Finally, all the TPS composite films showed low changes in terms of optical properties and equilibrium moisture, being less soluble in water than the TPSDH films. |
topic |
waste valorization rice straw thermoplastic starch cellulose thermal modification microcomposites |
url |
https://www.mdpi.com/2076-3417/11/18/8433 |
work_keys_str_mv |
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