Plastic Elongation

Generally, a plastic with a high degree of toughness is desired in food packaging application. The plastic which is able to resist any breakage under tensile strength is preferred. These can be achieved by exert the plastic films with the characteristics like high tensile strength and high degree of elongation. A packaging material or plastic material which is brittle in natures, and with poor tensile strength and flexibility will have a minimal use in food packaging industry.

Basically, tensile strength can be defined as the maximum tensile stress that the plastic can sustain without being fractured. It is calculated by dividing the maximum load exerted on the plastics during the experiment by the initial cross section of the plastics. A high

It can be defined as the percentage of change of the original length of the plastic sample between the grips of the texture analyzer. In an unwinding process, the elongation characteristic of the plastic is particularly important, as if the elongation is too low, the plastic sample will break due to the sudden imbalance that occurred during the unwinding process. Besides, elongation is related to the flexibility of one plastic film too.

Some errors happened during the test, which may influence or affecting the result. First, during the marking of the plastic film by using pen, some pressure had been exerted onto some of the plastic sample, which could affect the results afterwards. Secondly, the clip which was used to position the plastic film is sometime being not properly clipped, so it could affect the result

The entire sample that had been test is a thermoplastic, were elastic and clear is their properties. But for the PE, have a different with other at polimer structure which is, PEA is more to LLDPE (linear light density polyethylene). LLDPE have no long chain branch but have numerous short side chain where the tensile strength can be increase by apply close pack or crystallise to this plastic. The other sample can be crystallise too, but base on their polymer arrangement is long chain branch make them less coefficiency in increasing the tensile strength. The random short and long branches in LDPE cause the low crystallinity of LDPE (50-70% crystallinity) and low density. The relatively low tensile strength of PE was due to low crystallinity and low molar mass (Gumargalieva&Zaikov, 2003). OPP should have more tensile strength because due to the orientation of molecular chains in a predetermined direction. According to Kirwan& Strawbridge (2003), orientation of plastic film in both the machine and transverse direction could increases the tensile strength of film because orienting the film molecular chain in one direction make the polymer chains closely binds to each other. For based on the result, OPP gives high tensile strength than