Physical Properties of Plastic Packaging Systems
To decipher physical features and specifications of plastic polymers, primary features such as molecular weight, molecular structure (MW), polymer type, and transparency must be regarded. Thermoplastic polymers are almost globally utilized in the food packaging sector due to its several characteristics:
- Comparatively lengthier chain molecules, frequently without branching
- Solvent solubility which might include bio polymeric system and water
- Possessing a specific degree of rigidity or flexibility
- Semi crystalline structure, and/or formless crystalline structure
- Highly incendiary in comparison to other types of packaging materials
- Accepted degree of viscosity; which can flow under temperature and pressure
Normally, polymers need to produce a minimum molecular mass higher than 25000g/mol for physical features to be helpful for packaging substances.
Normally, the molecular mass of polymers also needs to produce a minimum higher than 25000g/mol for physical features to be helpful for packaging substances. The tensile power of packaging products rises only with the increment of MW polymer.
It is significant to measure the degree of cloudy and transparent Plastic Packaging and find out how it can be used. The inconsistencies in the surface also affect the features of both opaque and transparent plastic. There are microscopic and macroscopic inconsistencies in it. There are certain plastic polymers which have been utilized in food packaging and have a high degree of transparency which offers a function congruent to a glass packaging system. This exclusive feature can be altered by both physical and chemical applications on either products or polymers and then used in the diverse types of food products.
Gloss can have a substantial degree of value in the optical properties, and it mainly explains the surface area. A distinct degree of gloss could alter the perception of and the consumer’s perspective about the package. On the other hand, packaging restricts gas and light penetration which in turn is crucial to raising the shelf life of some food items.
Presently, more colored packages have been brought/introduced into the commercial market to appeal to more buyers, who can also be appealed to by the superior first impression of the food items. Color is the feature pinpointed by one or the five human sense organs, and is linked with recognizing and comprehending several materials existing in our lives.
Examination techniques for physical features
Molecular Weight Determination
The firm interrelationship between molecular weights of plastic polymers and physical features, estimating the molecular weight of plastic substances is vital for the use of packaging. Normally, to ensure the power of packaging items, it is vital to remain assured that the quality of the whole packaging method is highly reliant on MW and its distribution. Fundamentally, there are two practical testing processes to find out the average MW and MW delivery of plastic substances. The two examinations are GPC (Gel Permeation Chromatography) and SEC (Size-Exclusion Chromatography). The mechanism of both these examinations is founded on steric isolation of the analytic molecules from the holes of the column packing material.
In the present consumer item business, color is one of the most basic/primary /fundamental determinants for communication with customers since it affects the initial impression, recognition, perception and parts of both quality and brand identity. For instance, most international brand products, trademarks, icons are meticulously linked to various special colors. Hence, exact and continuous color measurements are required in terms of controlling quality for the packaging system, which also covered labelling and printing. To find out the color of most packaged products, several types of spectroscopic tools, spectrometers, color data software, spectrophotometers and tools are utilized by scientists dealing with packaging.
Primarily, calorimeters can estimate the color of packaging films. For example, the light differences can be traced by different light reflectance of objects and films, total color difference (delta E*) along with color values (L*,a*, b*) is gathered.
Opacity is defined as the degree of pigmentation of packaging components found in black light. Opacity is helpful for packaging materials which are subtle to both ultraviolent light and visible light. The basic optical features of plastics which are examined are visible light absorption, gloss, refractive index, Ultraviolet rays, haze, yellowness index and color analysis along with transmission. These can be measured and analyzed by using a spectrophotometer.
The amount of light reflected by the surface of the material is called gloss. It is estimated at the angles of 85°, 20° and 40°. Haze is defined as the dispersion of light through a material which leads to a glaring sensation. The changes in color from pure white to yellow is estimated by the yellowness index.