Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene

In the competitive market of plastic fillers, inexpensive and reliable materials are always sought after. Using a method of thermal conversion called pyrolysis, a potential contender was created from a plant biomass known as soybean hulls (SBH). SBH are a byproduct of the soybean farming industry an...

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Main Authors: Collin Coben, Erol Sancaktar
Format: Article
Language:English
Published: MDPI AG 2021-11-01
Series:Sustainable Chemistry
Subjects:
Online Access:https://www.mdpi.com/2673-4079/2/4/35
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author Collin Coben
Erol Sancaktar
author_facet Collin Coben
Erol Sancaktar
author_sort Collin Coben
collection DOAJ
description In the competitive market of plastic fillers, inexpensive and reliable materials are always sought after. Using a method of thermal conversion called pyrolysis, a potential contender was created from a plant biomass known as soybean hulls (SBH). SBH are a byproduct of the soybean farming industry and represent an abundant and inexpensive feedstock. The thermal conversion of SBH material gives rise to a lightweight carbon-rich filler called pyrolyzed soybean hulls (PSBH). We created two separate lots, lots A and B, with lot A corresponding to SBH pyrolyzed at 450 °C (PSBH-A) and lot B corresponding to SBH pyrolyzed at 500 °C (PSBH-B). Both lots of PSBH were also milled to reduce their particle size and tested against the as-received PSBH fillers. These milled materials were designated as ground soybean hulls (GSBH). Two different polyolefins, linear low-density polyethylene (LLDPE) and polypropylene (PP), were used for this study. The PSBH fillers were added to the polyolefins in weight percentages of 10%, 20%, 30%, 40%, and 50%, with the resulting plastic/PSBH composites being tested for their mechanical, thermal, and water absorption properties. In general, the addition of filler increased the maximum stress of the LLDPE/PSBH composites while reducing maximum stress of the PP/PSBH composites. The strain at maximum stress was reduced with increasing amounts of the PSBH filler for all composites. The modulus of elasticity generally increased with increasing filler amount. For thermal properties, the addition of the PSBH filler increased the heat distortion temperature, increased the thermal decomposition temperature, and reduced the heat of fusion of the composites compared to the neat polyolefins. The liquid absorption and thickness swelling in the materials were small overall but did increase with increasing amounts of the PSBH filler and with the time spent submerged in liquid. Milling the PSBH material into GSBH generally had small effects on the various tested material properties and led to easier mixing and a smoother finish on the surface of processed samples. The differences observed between lot A and lot B composites were often small or even negligible.
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spelling doaj.art-7acd1e93404f442697113d895d6790a72023-11-23T10:35:35ZengMDPI AGSustainable Chemistry2673-40792021-11-012462264410.3390/suschem2040035Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density PolyethyleneCollin Coben0Erol Sancaktar1Polymer Engineering Department, University of Akron, Akron, OH 44325, USAPolymer Engineering Department, University of Akron, Akron, OH 44325, USAIn the competitive market of plastic fillers, inexpensive and reliable materials are always sought after. Using a method of thermal conversion called pyrolysis, a potential contender was created from a plant biomass known as soybean hulls (SBH). SBH are a byproduct of the soybean farming industry and represent an abundant and inexpensive feedstock. The thermal conversion of SBH material gives rise to a lightweight carbon-rich filler called pyrolyzed soybean hulls (PSBH). We created two separate lots, lots A and B, with lot A corresponding to SBH pyrolyzed at 450 °C (PSBH-A) and lot B corresponding to SBH pyrolyzed at 500 °C (PSBH-B). Both lots of PSBH were also milled to reduce their particle size and tested against the as-received PSBH fillers. These milled materials were designated as ground soybean hulls (GSBH). Two different polyolefins, linear low-density polyethylene (LLDPE) and polypropylene (PP), were used for this study. The PSBH fillers were added to the polyolefins in weight percentages of 10%, 20%, 30%, 40%, and 50%, with the resulting plastic/PSBH composites being tested for their mechanical, thermal, and water absorption properties. In general, the addition of filler increased the maximum stress of the LLDPE/PSBH composites while reducing maximum stress of the PP/PSBH composites. The strain at maximum stress was reduced with increasing amounts of the PSBH filler for all composites. The modulus of elasticity generally increased with increasing filler amount. For thermal properties, the addition of the PSBH filler increased the heat distortion temperature, increased the thermal decomposition temperature, and reduced the heat of fusion of the composites compared to the neat polyolefins. The liquid absorption and thickness swelling in the materials were small overall but did increase with increasing amounts of the PSBH filler and with the time spent submerged in liquid. Milling the PSBH material into GSBH generally had small effects on the various tested material properties and led to easier mixing and a smoother finish on the surface of processed samples. The differences observed between lot A and lot B composites were often small or even negligible.https://www.mdpi.com/2673-4079/2/4/35sustainabilitysoybean hullsfilled polypropylenefilled linear low density polyethylenepyrolysisball milling
spellingShingle Collin Coben
Erol Sancaktar
Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
Sustainable Chemistry
sustainability
soybean hulls
filled polypropylene
filled linear low density polyethylene
pyrolysis
ball milling
title Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
title_full Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
title_fullStr Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
title_full_unstemmed Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
title_short Use of Pyrolyzed Soybean Hulls as Fillers in Polypropylene and Linear Low Density Polyethylene
title_sort use of pyrolyzed soybean hulls as fillers in polypropylene and linear low density polyethylene
topic sustainability
soybean hulls
filled polypropylene
filled linear low density polyethylene
pyrolysis
ball milling
url https://www.mdpi.com/2673-4079/2/4/35
work_keys_str_mv AT collincoben useofpyrolyzedsoybeanhullsasfillersinpolypropyleneandlinearlowdensitypolyethylene
AT erolsancaktar useofpyrolyzedsoybeanhullsasfillersinpolypropyleneandlinearlowdensitypolyethylene