Properties and environmental impact evaluation of the styrene-methyl methacrylate copolymer cast sheet process modified by deproteinized natural rubber
Abstract:
This research presents the properties and environmental impact
evaluation of the transparent styrene-methyl methacrylate (S-MMA) copolymer cast
sheet process modified by deproteinized natural rubber (DPNR) via bulk
polymerization. Influencing factors, such as monomer ratio and concentration of
DPNR, on the preparation of the transparent S-MMA copolymer cast sheets were
studied. The mechanical properties of the transparent S-MMA copolymer cast sheet
were also examined, such as impact strength, Shore D hardness, and tensile
properties; as well as physical properties, such as opacity, heat resistance, and
ultraviolet resistance.
The appropriate concentrations of S and DPNR for the preparation of the
transparent S-MMA copolymer cast sheets were 20% w/w and 2% w/w,
respectively. The mechanical and physical properties were as follows: Shore D
hardness 84.15 ± 0.24/10, Izod impact strength 60.65 ± 0.37 kJ/m2, tensile stress at
yield 39.96 ± 1.59 MPa, and elongation at break 4.45 ± 0.35%, the yellowness shifts
of the ultraviolet resistance (ΔΕ) 6.47 ± 0.26, ΔΕ of the heat resistance 4.12 ± 0.28
and opacity value 13.26 ± 0.61%. The results showed that Shore D hardness and
tensile stress at yield decreased with increasing DPNR and S concentrations. On the
other hand, impact strength and elongation at break of the transparent S-MMA
copolymer cast sheets increased with increasing amounts of DPNR and S. The
concentrations of DPNR and S did not affect the transparency of the S-MMA
copolymer cast sheets.
Finally, the environmental impact of the impact modified S-MMA cast
sheet using DPNR was evaluated by using the life cycle inventory (LCI) data for
material grouping according to environmental and material properties. The use of
DPNR as an impact modifier compared to the use of synthetic rubber shows the
decrease of natural consumption, pollution and investment cost, which demonstrates
the eco-efficiency of the transparent S-MMA copolymer cast sheet production by
using DPNR as an impact modifier