Chapter 1

INTRODUCTION

A.Background of the study

The use of adhesives offers many advantages over binding techniques such as sewing, mechanical fastening, thermal bonding, etc. These include the ability to bind different materials together, to distribute stress more efficiently across the joint, the cost effectiveness of an easily mechanized process, an improvement in aesthetic design, and increased design flexibility. The researcher will make glue out of milk to improved the stickness of milk.

An adhesive is any substance applied to the surfaces of materials that binds them together and resists separation.Adhesives may be found naturally or produced synthetically.These are then organized into reactive and non-reactive adhesives, which refers to whether the adhesive chemical reacts in order to harden. Alternatively they can be organized by whether the raw stock is of natural or synthetic origin, or by their starting physical phrase. Adhesive is classified in different material like glue,cement, beewax etc.Disadvantages of adhesive use include decreased stability at high temperatures, relative weakness in bonding large objects with a small bonding surface area, and greater difficulty in separating objects during testing.

The researcher chooses this project because I'm interested of this topic. I know that this project is already been done by other people.Adhesive play the important role of the stickness of the raw materials to improved the joined material.This project also gives the researcherand the reader additonal knowledge about the difference between the types of adhesive.

B.Theoretical / Conceptual Framework

Adhesion Theory,Several theories of adhesion exist which are based on surface-chemical phenomena. It is generally considered that there is no generalised, unified theory of adhesion since the phenomenon is known to exist between a great diversity of material types. In some special cases, either pure adsorption, or electrical or diffusion attractive forces are found at an adhesive-bound interface.More frequently, one finds adhesion to be a synergistic combination of all of these driving, attractive forces. This is expecially true in the case of practically all adhesive bonding situations.

Adsorption Theory-In adsorption theory the attractive forces between materials is interpreted in terms of the chemisorbed and physisorbed atomic and molecular species that exist at an interface. Essentially this theory regards adhesion as one particular property of a phase interface wherein polar molecules or groupings will be orientated in an ordered way. The forces are initially involved in this mechanism are the van de Waals' forces - the orientation, induction and dispersion effects. If a molecule, which is large enough to contain a polar group and a non-polar part as separate and distinct entities, approaches an interface at which the dielectic constant changes it will orientate itself. It will move so that its non-polar part will be in the medium of lower dielectic constant and its polar part in the medium of high dielectic constant. This is the process that takes place in adsorption and must really take place if an adsorption theory is valid.
Electrical Theory-This theory explains adhesive attraction forces in terms of electrostatic effects at an interface. This is based on the phenomenon of a electrical double layer formed at the junction of two materials. At any boundary an electrical double layer is produced and the consequent coulombic attraction might account for the adhesion and resistance to separation.

Diffusion Theory- In this theory adhesion is attributed to intermolecular entanglements at the interface. This is applied to the union of high polymers. The fundamental concept is that adhesion arises through the interdiffusion of the adherend and the adhesive. It is based upon the chain nature of the structure with the consequent flexibility and the ability of the chains to undergo Brownian movements on a sub-molecular scale. When the adhesive is applied in solution (most probably) and if the adherend is sensibly soluable in the solvent the substrate molecules will also diffuse to an appreciable extent into the adhesive layer. Overall the clean-cut boundary between the adherend and the adhesive disappears and is replaced by a layer representing a gradual transition from one polymer to the other. A major difference in this theory is that it implies a three dimensional volume process rather than a two dimensional surface process.

B.Statement of the Problem

This study focuses on comparing effectivity of noise cancellation.It seeks to answer the following questions: Is Adhesive can be effective when you bind the metal together? Is Adhesive is important? Which is better Homemade glue or commercial glue(elmer's,pritt, mighty bond)?

C.Hyphotheses

The researcher formulate the following question:

You can't really join metals with adhesive not with ordinary glue,but you can join them by melting them together in a process known as welding. Yes,adhesive is important because without adhesive we can't bind things together. Commercial Glue are most better because it is combined with other chemical materials that can make the binding strong.

D.Significance of the study

The researcher believes that the study will beneficial to the following groups: To the students. The study will beneficial to them because the result of stickness of the milk will improvised their project like popsicle house, paper mache and etc without expensing big money. To aspiring people. The study will beneficial to them because the glue will improvise also their works like in the agency,they use glue for advertise them.

E.Scope and Limitations

The investigatory project focuses on the processes of adhesive and the stickness of milk.It focuses on stickness which is subject Chemistry.The aspects were covered by the study is that students don’t to buy commercial glues which are expensive. They can just make their own glue using milk and other ingredients which are only found in the house.
The limitations of the study that we should know is that to make homemade glue using only materials found in our house no need to buy expensive glue. Just make your own homemade glue, it’s easy and affordable.

F. Definitions of terms

Adhesive- is any substance applied to the surfaces of materials that binds them together and resists separation.
Glue -a kind of adhesive.
Milk-is a white liquid produced by the mammary glands of mammals.
Diffusion-is the net movement of molecules or atoms from a region of high concentration to a region of low concentration.
Adsorption- is the adhesion of atoms,ions,or molecule from a gas,liquid or dissolved solid to a surface.