eChapters

Objective
After performing this experiment, you will be able to learn
Sorting of given samples by selective dissolution technique.
Introduction
Sorting process is the process of separating the mingled and mixed plastic before the recycling process. 

Selective Dissolution Technique (SDP)

Recycling of plastic has become the major focus nowadays. Sorting of plastic materials is the major step towards recycling. One of the sorting techniques is selective dissolution although it has not found major usage in industry for various drawbacks. This technique uses the solubility parameter of different polymers for segregation purpose. Each polymer owing to its chemical structure has different solubility parameters. Hence, the solvents for each and every polymer are different. This difference in solubility in different solvents is used here for separating them from one another.

Recycling of plastic has become the major focus nowadays. Sorting of plastic materials is the major step towards recycling. One of the sorting techniques is selective dissolution although it has not found major usage in industry for various drawbacks. This technique uses the solubility parameter of different polymers for segregation purpose. Each polymer owing to its chemical structure has different solubility parameters. Hence, the solvents for each and every polymer are different. This difference in solubility in different solvents is used here for separating them from one another.

Objective

After performing this experiment, you will be able to learn

Sorting of samples by sink-floatation technique.

Introduction

Sink float is the simplest and cheapest method among all the wet sorting techniques in which polymers are separated based on their density. This technique is extremely fast, environment friendly and cost effective process for sorting of plastics. Since, the separations are done based on density, so any factor which may change the density of the pure polymer like blending, composite formation of multilayer structures etc. will not be separated well using this method. Moreover, if any two polymers are very close in density, they cannot be separated easily. That is why PVC and PET which are very close in their density can not be separated using sink floatation method.

Initially the plastic waste is added to the container containing water and the system is gently stirred to evenly wet the surface of plastic and remove any air trapped on the surface. Since the density of polyolefins is near/close to each other but lighter than water, they all float in water whereas the heavier plastics sink. This technique is primarily used to separate polyolefins from other plastics. Now to further segregate the polyolefinic fraction, this method is extended by adding the polyolefin mixture to another container containing water and alcohol. As dropwise more and more alcohol are added to the water, the density of the medium will decrease and the polyolefins start separating. For separating the heavier fraction of the polymer, the mixture of polymers is added to water. To this water, dropwise salt water is added and stirred. Salt water increases the density of the medium slowly and at one point, the polymers which were sinking in water, will start floating depending on their density.

Object: To demonstrate anaerobic respiration. 

Material required: Soaked pea or gram seeds, mercury, test tube stand, forceps and KOH pellets. 

Theory: Generally, plants at certain stage have the capacity to respire in absence of oxygen i.e. anaerobic respiration. In this process, oxidation of carbohydrate takes places, ethyl alcohol and CO2 being end products and only a little amount of energy is liberated-

Object: To demonstrate chlorophyll fluorescence.

Material required: Spectrophotometer, fresh green spinach, mortar, pestle, acid washed sand, acetone, funnel, filter paper and test tubes.

Principle: Chlorophyll molecule absorbs light in the blue (450nm) and red (660nm) region and get into excited state and emits an electron. The electron drops back to the ground state within 10-9 seconds and some energy (which is not used in biochemical reaction) are given out as the observed fluorescent far red light.

Procedure and observation: Take some soft green spinach leaves. Grind these with a pestle -mortar in acetone adding a pinch of acid washed sand. Make a fine paste. Filter to get a clear solution in a test tube. Take the test tube in bright sun light.

Object: To demonstrate that light and carbon dioxide are essential for photosynthesis (Moll’s half leaf experiment). 

Material Required: A potted plant, a wide mouthed bottle, caustic potash, splits of rubber Cork and vaseline etc. 

Object: To demonstrate that O₂ is evolved during photosynthesis. 
 

Material required: Hydrilla plant, beaker, test tube, funnel, pond water and pyrogallol. 
 

Theory: Oxygen is a byproduct of photosynthesis, which is evolved in presence of light and chlorophyll during photosynthesis.

Object: To demonstrate that oxygen is used up during respiration. 

Material required: A conical flask, some germinating seeds, glass tube having two bends at right angles, mercury, beaker, small tube and caustic potash (KOH).

Theory: Plants at some stage have a capacity to respire more rapidly in presence of oxygen i.e. aerobic respiration. In this process, oxidation of carbohydrate occurs resulting in conversion of carbohydrate into carbon dioxide (CO₂) and water with release of large amount of energy.

Object: To demonstrate that water is lost from a living plant during transpiration. 

Material Required: A potted healthy plant, a bell jar, a rubber sheet or oil cloth, a glass sheet and grease.

Theory: Transpiration: Loss of water in the form of water vapour from the internal tissues of living plants through aerial parts of the plant is known as transpiration.

Object: To demonstrate the measurement of growth in plants with the help of Arc auxanometer. 

Material required: Potted plant, Arc auxanometer, rope and weight.

Theory: Growth is a permanent change in plants with respect to its size, form, weight and volume.

Object: To demonstrate the optimum conditions for seed germination. 

Material required: Beaker, glass slide, bean seeds, thread and water.

Theory: Germination is a process by which the embryo in the seed becomes activated and begins to grow into a new seedling under favorable conditions. Food is stored in the seeds in dry conditions but the developing embryo cannot utilize this dry food. Food can be utilized in liquid form only and seeds can utilize only dissolved oxygen. Excess water stop germination because once all the dissolves oxygen is utilized by the seed, further germination is not possible as the life supporting oxygen is lacking. Suitable temperature is necessary because low temperature retards the embryo activity and high temperature destroys the delicate embryo tissue. Seed usually germinate between 0oC to 50oC temperature and the optimum temperature is lies between 25 to 30oC. During germination rapid cell division takes place. Energy is required for cell division. This energy is obtained from oxidation. The oxygen is required for oxidation is supplied by the air.

Object: To demonstrate the phenomenon of endosmosis and exosmosis by using grapes and raisins.

Material required: Grapes, raisins, beaker or petridish, water and sugar solution.

Object: To demonstrate the phenomenon of osmosis using potato osmoscope. 

Material required: A potato tuber, sugar solution, beaker, water, petridish, knife, measuring cylinder, and stand.

Theory: Osmosis is a phenomenon in which water molecules diffuse through the semi permeable membrane from region of its higher concentration to the region of lower concentration.

Object: To demonstrate the process of diffusion.

Material required: Beakers, copper sulphate, distilled water and sugar solution.

Object: To demonstrate unequal transpiration by the two leaf surfaces from four leaf method. 

Material required: four leaves of china rose or any dorsiventral leaves, two stands, thread and grease or vaseline. 

Theory: Transpiration is a process in which loss of water occurs in the form of water vapour from the aerial parts of the living plant. 

Method: Take four leaves of equal size from a plant (e.g. China rose). Now apply or smear the vaseline on the four leaves as follows:

Object: To determine respiratory quotient of different types of respiratory substrates.

Objective
After performing this experiment you will be able to learn:
How to  determine the caliper/GSM of paperboard.

Introduction

Thickness is calculated as the perpendicular distance between the two principle surfaces of paper or paperboard as measured under specified conditions. The GSM of paper may be defined as the thickness of a paper that is measured in a roundabout way. GSM stands for Gms per Square Metre - and is used to check the quality of the paper to be measured.

It is a very simple to perform test but tells a lot about the basic properties of the material which are very important to decide the quality of the material. Also, the quality of the material is measured with its GSM value. The heavier a paperboard is, the better the quality.

Principle

Packaging materials are chosen by estimating the GSM of the sample material. High Grammage defines the strength of the paper. In certain applications high Grammage is desired, where the paper will be subjected to load and harsh working conditions.

Objective
After performing this experiment you will be able to learn:
The impact properties of polymeric film.

Introduction

Dart impact test is performed on plastic films and laminates to determine the effect of free falling dart on plastic films. The energy created by the falling dart causes the film to fail under some specified conditions. The test is widely performed by the manufacturers in plastic industries and paper & packaging industries to assess the durability and strength of the plastic films and other related products.

Dart impact strength is dependent on film thickness as the test is sensitive to orientation of the chains in the film. The tackiness of the film (slip additives) and the condition of the dart surface also influence the values determined by this test. As dart impact is not tested in any specific film direction, it is sensitive to chain orientation in both directions. Best impact strength are usually obtained when the orientation is balanced in the Machine Direction and Cross Direction.

Principle

The test method is according to ASTM D1709

Objective
After performing this experiment you will be able to:
To determine the peel strength of a given samples.
Introduction

Packaging is a key element to quality branding for an organisation, ensuring that the product labels are securely attached to products. Adhesion bond strength of a film to a surface can be quantified in terms of peel strength, bonding strength, and shear strength. Many protective covers are used as required for various applications. In most of such applications plastics films are used as the first preference of the manufacturers. In applications like, protective LCD screens and other scratch-prone surfaces very low peel force films are used. The force required to remove the protective films or the label is very important for both the consumer and the manufacturer. For example, for protective film application, the film must be easy to remove, yet the bond must be strong enough to remain intact for product security. Whereas, in a typical adhesive application, like laminated cups, the bond between the surfaces should be strong enough to withstand various environmental impact.

Objective

After performing this experiment you will be able to learn:

To determine the tear resistance of polymeric film.

Introduction

Tear resistance testing is often used in the plastic film, paper and textile industries. Tear resistance is measured as a sample's ability to resist tearing. Tear strength is the maximum london the sample divided by the thickness of the material. Typically used for testing of plastic film, plastic sheets and other rubber products. Tear strength is calculated by force (in Newtons) divided by thickness (in millimeters, centimeters, inches, etc.): Tear strength = F/t

A tear is generally uneven and usually unplanned. In cases like a packaged chips, already tear cuts are made following a perforated line so that the effort of tearing is less and the action will most likely produce a straight line.

The speed at which a tear resistance test is conducted can affect the test significantly. Tear transmission resistance is common for acceptance testing with materials such as paper and rubber. Tear resistance in textiles involves the load required to spread a single "rip-tongue" type of tear or the type of tear where the material is initially cut.

Objective
After performing this experiment you will be able to learn:
To determine the tensile properties of polymeric sample.
Principle

ASTM D638 covers the tensile properties of both reinforced and unreinforced plastics in the form of dumbbell-shaped molded plastic test specimens.

Yield strength is measured as the highest stress where a film, when deformed, will resume its original dimensions when the force is removed. The yield stress is expressed as force per unit area (engineering stress) and is calculated as per Equation (1) and the elongation at yield as per equation (2).