Citation: Tor-
´
Swi ˛atek, A.; Garbacz, T.;
Stloukal, P. Analysis of Selected
Properties of Microporous PLA as a
Result of Abiotic Degradation.
Materials 2022, 15, 3133. https://
doi.org/10.3390/ma15093133
Academic Editors: Izabela Nielsen,
Alessandro Pegoretti,
Halina Kaczmarek and Gang Wei
Received: 21 February 2022
Accepted: 23 April 2022
Published: 26 April 2022
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Article
Analysis of Selected Properties of Microporous PLA as a Result
of Abiotic Degradation
Aneta Tor-
´
Swi ˛atek
1
, Tomasz Garbacz
1,
* and Petr Stloukal
2
1
Faculty of Mechanical Engineering, Lublin University of Technology, 36 Nadbystrzycka, Str.,
20-816 Lublin, Poland; a.tor@pollub.pl
2
Centre of Polymer Systems, Tomas Bata University in Zlin, Tˇr. T. Bati 5678, 760 01 Zlin, Czech Republic;
stloukal@utb.cz
* Correspondence: t.garbacz@pollub.pl
Abstract:
In the study, an investigation was made into the hydrolytic degradation behavior of the
microporous polylactide (PLA) in the initial stage in three biological buffer solutions with various
pH-simulating body fluids in comparison with pure PLA. Studies also include the analysis of selected
mechanical properties and physical structures. A microporous PLA was obtained by melt extrusion
using a chemical blowing agent. The rate of Mw decrease induced by hydrolysis over 35 days of
microporous PLA was roughly comparable to the pure material. The rate of depolymerization was
slightly accelerated at an acid pH due to acid-catalyzed hydrolysis at the end of the observed period.
The mechanical analysis showed the influence of various pH on the obtained results.
Keywords: polylactide; blowing agent; microporous extrusion process; thermal behavior
1. Introduction
Over the years, the world market for polymers has evolved towards the increased
use of environmentally friendly materials. The high interest of manufacturers in natu-
ral and biodegradable materials results from their willingness to meet the needs of the
ever-increasing group of consumers who value the “Zero Waste” principle. At the head
of this group of materials, which attracted the above-mentioned attention of manufactur-
ers, is polylactide (PLA), which is the most famous biodegradable material in the world
and should be undoubtedly mentioned. Despite its many advantages, PLA is a relatively
expensive material, which has an impact on its applicability. PLA is a material that can suc-
cessfully replace other commonly used plastics such as polypropylene (PP) or polystyrene
(PS) in packaging applications [
1
–
8
], automotive [
9
,
10
], consumer goods, electronics [
11
,
12
],
3D printing applications [13–17], and biomedical devices [18,19].
In order to reduce the manufacturing costs and improve the selected mechanical and
physicochemical properties, modifications of polylactide are applied, and its biodiversity
is maintained. The most frequently applied modifications include mixtures with other
polymers, such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT),
or the increasingly used poly (butylene adipale-co-terephthalat (PBAT) [
20
–
26
]. Often,
research related to the composition of PLA with PA (polyamides) and its different types
and applications is undertaken [27–29].
Numerous studies on the various property changes of the modified PLA materials
with powder and fiber additives are also highly interesting [
30
–
34
]. Powder additives, such
as talc [
35
,
36
] and basalt [
37
,
38
], are commonly used in research. Nevertheless, more often
than not, organic fiber additives are applicable. Its usage depends on its availability in the
particular country and region where that type of fiber waste is produced. The research
was conducted to determine the suitability of these types of fillers for modification of PLA
concerns, and, among others, sisal [
39
,
40
], jute [
41
], kenal [
42
], cotton [
43
], bamboo [
44
,
45
],
and, most of all, flax [46–50].
Materials 2022, 15, 3133. https://doi.org/10.3390/ma15093133 https://www.mdpi.com/journal/materials
