Page 356 - Biodegradable Polyesters

334 13 Biodegradable Polyester-Based Blends and Composites

Package applications include drinking cups, containers, wrappings, sundae and
salad cups, blister packages, lamination films, and water bottles [88]. Currently,
natural fiber reinforced biodegradable polyester-based composites are used in
compostable yard bags to support regional or national composting programs.
Coir/PLA composites are used in novel applications, such as cardboard or
paper coatings, for example, those used in the fast-food markets (plates and
cups) [94]. However, to cater to a wide variety of proportioned markets, some
demerits of polyester-based composites must be overcome, such as its poor
mechanical properties and heat resistance. In order to meet market demand,
the world manufacture of biodegradable polyester-based composites must be
increased. Since 2009, there has been an increasing trend for applications of
these composites in the bio-based markets, such as in automotive and building
applications. Specifically, natural fiber reinforced composites, in particular
sisal/PLA, flax/PHB, coir/PLA, jute/PLA, hemp/PHB, and jute/PHB composites,
can be used in car bumpers, seats, door, and window panels, insulation, and so
on [52, 56, 95–97]. Sisal/PLA composites can be used to repair roof cracks and
support lightweight structural components [95] and coir/PLA composites can be
used in lightweight constructions [97].
PLA-based composites used in packaging can offer enhanced mechanical prop-
erties compared to those of polystyrene, and have properties similar to those of
poly(ethylene terephthalate) (PET) [94, 98–100]. Market studies show that PLA
composites are reasonably feasible as packaging material. With its current con-
sumption rate in the market, PLA composites are used as an important source in
terms of volume for biodegradable packaging [98, 99]. Since PLA self-reinforced
composites are expensive, the preliminary use of PLA as packaging material has
been in rigid thermoforms, high-value films, coated papers, and food and bever-
age containers. One of the earliest companies to use PLA composites as packaging
material was Danone (France) in yoghurt cups for the German market in the late
1990s [85]. But the manufacture of these cups was quickly discontinued. In 2011,
Danone launched new degradable yoghurt cups for the German market with huge
success. Over the last decade, the use of PLA and its composites as packaging
material has expanded all across Europe, the United States, and Japan, chiefly in
the area of fresh goods. The main advantages of polyester-based biodegradable
composites are the high bio-based content and the equivalent mechanical prop-
erties [57].

13.6
Summary

A wide range of biodegradable polyester-based composites is available in the new
era of novel materials. Polyester-based composites are mainly manufactured by
reinforcing with glass/carbon and natural fibers. The use of natural fibers as rein-
forcement has increased in the last two decades, because of their easy availability
and degradable property. Polyester composites reinforced by glass or carbon fibers