Maize–Natural Fiber as Reinforcement with Polymers for Structural Applications - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 36

acid component. The finished polymer is dissolved in a reactive monomer such as
styrene to give a low viscosity liquid. When this resin is cured, the monomer reacts
with the unsaturated sites on the polymer converting it to a solid thermoset structure.
Natural fiber materials have a long history of use in construction since Egyptian
period. They were widely used in straw bale houses and straw mud houses. Biologi-
cal renewable sources are novel materials for construction purposes (Herrmann et al.,
1998). Polymers are widely used as reinforcement in structures of civil construction,
in strengthening of bridge girders, bridge decks, cable stayed bridges, columns, and
walls (Sheikh, 2002; Uomoto et al., 2002). Researchers (Dweib et al., 2004, 2006)
developed structural members like panels from natural composite materials that can be
used for roofs, floors, or in low-commercial building. A bio-based material reinforce-
ment by natural fibers was carried out and these structural beams were successfully
manufactured and mechanically tested giving good results.
The main aim of the work is to focus on maize fibers for reinforcement with ther-
mosetting polymers in the process of vacuum assisted RTM and examine the prepared
composite material. Natural fibers reinforced polymers have large advantages such
as high specific properties, high mechanical properties, low density, low weight, and
low cost. The study focused much on maize stalk based fiber its chemical and thermal
properties and also its influence in thermosetting polymers.

table 1. Fiber structure and properties of some agricultural residues ( Reddy and Yang 2005).

Fiber St ructure Fiber Properties

Cell dimensions

Fiber

Crystallinity (%) Elongation (%) Moisture content (%)

Length
(mm)

Width
(µm)

Corn husk 0.5-1.5 10-20 48-50 12-18 9

Sorghum Stalk 0.8-1.2 30-80 - - 8-12

Rice straw 0.4-3.4 4-16 40 - 6.5

Wheat straw 0.4-3.2 8-34 55-65 - 10

Barley straw 0.7-3.1 7-24 - - 8-12

Maize is also known as corn in many English speaking countries. They are widely
used for many purposes like starch products, food, and fodder uses. Maize stems al-
most resemble bamboo canes and the internodes can reach 20-30 cm, the stems are
erect conventionally 2-3 m in height with many nodes casting off flag-leaves at ev-
ery node. The top producing countries are United States of America, China, Brazil,
Mexico, Indonesia, India, and other European countries.
Various researchers had found that stalk fibers have better properties than that of
the other parts of plant fiber and indicated that they can be used for composite and oth-
er industrial applications (Reddy and Yang, 2009). Natural fiber composite laminates with
distributed areca and maize stalk fibers using phenol formaldehyde were investigated
(Kumar, 2008). Composite laminates were prepared with different proportions of phenol
formaldehyde and fibers. Mechanical test such as tensile test, adhesion test, moisture