Recent Advances in Understanding the Role of Wastewater …
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1.3.2 Ionization
Ionization or protonation of a pendent group can help in solubilizing certain water
insoluble polymers. Polyacids can be made soluble and hence hydrophilic.
1.3.3 Hydrolysis and Enzyme-Catalyzed Hydrolysis
Polymers that are insoluble in water and containing ester groups can be made soluble
if the esters are hydrolyzed to form ionized acids on the polymer chain [4]. Enzymes
can also be used as catalysts for oxidation, reduction, hydrolysis and esterification
[13].
1.3.4 Microbial Degradations
One of the approaches to enhance biodegradability is to add natural polymers to
thermoplastics. These natural polymers could be made from bacteria, fungi, algae,
etc. Preparing biodegradable plastic encompasses addition of distinct additives to the
synthetic polymers, which make it prone to microbial degradation by breaking the
endurance of C–C chain of polymers [14].
1.4 Factors Affecting Polymer Degradation
1.4.1 Chemical Composition
The chemical configuration of the polymers is of great importance in its degradation.
Breaking down of polymers by microorganisms can be hindered by the presence
of polymers that contains only long carbon chains. Polymers can be made more
susceptible to biodegradation by introducing hetero-groups such as oxygen in the
polymer chain [15].
1.4.2 Molecular Weight
The rate of plastic degradation reduces with increase in the molecular weight of
the plastics [16]. Linear plastic polymers with molecular weight lower than 620 can
support microbial growth [17].
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1.3.2 Ionization
Ionization or protonation of a pendent group can help in solubilizing certain water
insoluble polymers. Polyacids can be made soluble and hence hydrophilic.
1.3.3 Hydrolysis and Enzyme-Catalyzed Hydrolysis
Polymers that are insoluble in water and containing ester groups can be made soluble
if the esters are hydrolyzed to form ionized acids on the polymer chain [4]. Enzymes
can also be used as catalysts for oxidation, reduction, hydrolysis and esterification
[13].
1.3.4 Microbial Degradations
One of the approaches to enhance biodegradability is to add natural polymers to
thermoplastics. These natural polymers could be made from bacteria, fungi, algae,
etc. Preparing biodegradable plastic encompasses addition of distinct additives to the
synthetic polymers, which make it prone to microbial degradation by breaking the
endurance of C–C chain of polymers [14].
1.4 Factors Affecting Polymer Degradation
1.4.1 Chemical Composition
The chemical configuration of the polymers is of great importance in its degradation.
Breaking down of polymers by microorganisms can be hindered by the presence
of polymers that contains only long carbon chains. Polymers can be made more
susceptible to biodegradation by introducing hetero-groups such as oxygen in the
polymer chain [15].
1.4.2 Molecular Weight
The rate of plastic degradation reduces with increase in the molecular weight of
the plastics [16]. Linear plastic polymers with molecular weight lower than 620 can
support microbial growth [17].