Thermal properties of material (Tg, Tm, Td) are those properties that response to temperature. They can be studied by thermal analysis techniques including DSC, TGA, DTA and dielectric thermal analysis. The nanometer-sized of inorganic particles incorporated into the polymer matrix can improve thermal stability by acting as a superior thermal insulator and as a mass transport barrier to the volatile products generated during decomposition [117]. Khanna et al. [57] reported the thermal (TGA) analysis of the PVA/Ag nanocomposite. They observed that the decomposition profile starting at about 330 ◦C and continuing till about 430 ◦C. They also found the PVA/Ag nanocomposites have higher thermal stability than the PVA alone. Mbhele et al. [99] also observed that that the pure PVA starts decomposing at about 280 ◦C and …show more content…
They also reported that the thermal stability of PVA/A g nanocomposite was superior to that of pure PVA. Thermal (TGA) properties of the composite films have been studied by Uddin et al. [62] who observed that the first degradation temperature (below 300 ◦C) with no difference with the pure PVA. Whereas, the second degradation temperature (at the higher temperature region above 300 ◦C) of the film is ∼40 ◦C higher than that of pure PVA indicating enhanced thermal stability of nanocomposite films. Also, the DSC thermograph of the nanocomposite films was performed. It was found the pure PVA film exhibits melting peak at 227 ◦C . But the DSC melting peaks in the nanocomposite appear at 220 ◦C lowered by 7 ◦C with respect to pure PVA film. Ananth et al. [58] studied the DSC analysis for the in-situ and ex-situ synthesis of the PVA/ Ag nanocomposites films. They found that (in the case of ex-situ PVA/Ag) the increase in the Tg after the incorporation of Ag nanoparticles into the PVA. The authors explained this behavior on the basis of interactions of the embedded Ag nanoparticles with the PVA chains resulting in the reduction in the
The nano-thermal analysis method is capable of studying the specific regions of a sample irrespective of its composition. In a multi-component sample, the analysis methods make it possible for the researchers to distinguish between the different components and identify the different characteristics found in each of the sample (Craig, 2002). During the analysis of any sample, the nano-thermal method does not necessarily require the physical alteration of the sample. In its place, it is capable of analyzing any sample through surface studies.
Have you ever wondered why the plastic bag that you left on the porch during winter cracks or breaks more easily than when you left it during summer time but a piece of wood which was left just like the plastic bag has no effect whatsoever? This is because of a phenomenon, which only happens to polymers, known as the glass transition. For each polymer, there is a certain temperature at which the amorphous polymers undergo a second order phase transition from a rubbery and viscous amorphous solid to a brittle and glassy amorphous solid called the glass transition temperature, Tg.1 When the polymer, or in this case, the plastic bag, is cooled below their glass transition temperature, it becomes hard and brittle like a glass but when it is used above their glass transition temperatures, it might have a different effect than when used at room temperature or below the glass transition temperature as normally, different types of polymers like clothes, food packaging, insulations for wires, etc. are either used above their glass transition temperatures or
Today, polyvinyl chloride (PVC) is used in many different products across the world. According to the APHA (2011), the material can be found in toys, medical supplies, floors, and even food wrapping. (p. 1) I believe that this material has made it possible for a lot of products to be made that have benefited the human population, but I believe there are many drawbacks to using this material.
Refrigeration is the process of cooling down a space or thing below normal environmental temperature. Food preservation is vital in today’s day and age. From the meats to the dairy, everything needs to be kept at room temperature, cold, or frozen. People even like to make themselves cold and frozen by using air conditioning. But, it does make you wonder “how” and “when”. How did refrigeration become such an important invention and how did people survive without it? When did our ancestors realize it takes the cold to keep their food preserved and looking fresh? We now have fridges that have an automated ice machine and touch screens.
In the section of Over Story: Zero, titled “Central Heat”, author Robert Heilman utilizes a soothing yet serene tone to convey the importance of home. Heilman’s eloquent language expresses that no matter the amount of strained or easily walked miles one may travel, no matter how many years of grief, joy, or pain pass by, or however the founding ideals of peace and family may change in the constant and chaotic pace of the growing new world, mankind will always be drawn to the warm and welcoming hearth of home. Heilman begins his subtle declaration by discussing how lucky the people of the Umpqua truly are that they are present within this new century of changing ideals and faster pace of life, and yet this people still understand the stories
In conclusion it was found that there is an inverse relationship between the strength of the intermolecular forces holding molecules together and the rate at which those molecules evaporate. As the bonds get stronger it takes more energy to separate them and allow the molecules to escape into the vapor phase. This was the goal of the lab and it was met. Significant improvements could only be made at a considerable investment in time and expense and are unnecessary as the lab procedure as outlined was more than enough to derive the relationship needed through comparison.
Investigating Heat Loss From a Container Planning We are investigating heat loss from a container and how it is affected. We could change: Room temperature Surface area Amount of water Use a lid Insulate around it Colour of tin We could measure / observe: Amount of time Temperature We will change: Surface area We will measure / observe: Temperature (every minute for 5 minutes) Our question is: Does surface area effect the rate of heat loss? We will keep these the same: Colour of tin Room temperature Amount of water Use a lid Insulate around it Preliminary investigation = == ==
The most commonly produced PVC structure by addition polymerisation is the atactic PVC. As seen in Figure #, the chlorine atoms are branched randomly and asymmetrically along the carbon backbone. Unlike the other two structures, the random orientation prevents the polymers from packing closely together and is described to be ‘amorphous’.
Have you ever been sitting there and just wondered about various things dealing with some things in chemistry known as calorimetry or thermochemistry? No, yes, maybe, well whatever your answer you were really thinking yes so I’m going to explain these topics to you in this paper, and teach you how they work so you can figure these things out if you ever run into them I a real life situation.
Heat energy is transferred through three ways- conduction, convection and radiation. All three are able to transfer heat from one place to another based off of different principles however, are all three are connected by the physics of heat. Let’s start with heat- what exactly is heat? We can understand heat by knowing that “heat is a thermal energy that flows from the warmer areas to the cooler areas, and the thermal energy is the total of all kinetic energies within a given system.” (Soffar, 2015) Now, we can explore the means to which heat is transferred and how each of them occurs. Heat is transferred through conduction at the molecular level and in simple terms, the transfers occurs through physical contact. In conduction, “the substance
Our project for the unit 2 test will be a candle and water demonstration. This will show the different relationships between temperature, pressure, and volume.
The main purpose of green nanotechnology has been to develop clean technologies that would minimize potential human and environmental health risk. Also, to encourage replacement of existing products with the clean technologies that is more environmentally friendly. There are many benefits of using green nanotechnologies as the new solution for energy in both their current availability and their current development. Over the new few decades, the highest growth opportunities will come from application of nanomaterials for making better use of existing resources. Nanotechnologies will help reduce weight of carbon emission in transportation utilizing nanocomposite materials that quickly diffuses across the automotive and aerospace industries. Applications of nanotechnologies will result in a global annual savings of 8000 tons of carbon dioxide, which will rise even further to over millions tons by 2020. But, let’s focus on the positive effects of Green Nanotechnology in Solar.
Have you ever taken a minute to wonder how heat in your everyday life is transferred from one object to another? Well, typically any heat that one feels throughout their day is most commonly transferred in one of three ways. Those three ways include conduction, convection, and radiation. The definitions of these three heat transfers are as follows. Conduction is specifically defined as, “the heat transfer through direct contact of molecules without any of the material as a whole” (Merriam-Webster's, 1999). A heat transfer via convection is also defined as, “the transfer of heat from one place to another by the movement of mass in liquid or gas form” (Merriam-Webster's, 1999). And finally heat radiation, is defined as, “the transfer of heat,
Life changed immensely in the 20th century as air conditioning and refrigeration systems became more efficient and controllable. Air Conditioning and Refrigeration play important roles in providing human comfort, food processing, storage, and many other industrial processes. We chose this topic because our life would be difficult without AC and Refrigeration. This paper will talk about the history of air conditioning and refrigeration, the role of engineers in designing and building it, people’s life before and after air conditioning and refrigeration, and finally Applications in the area of achievements and future developments.
Heat indulgence techniques are the prime concern to remove the waste heat produced by Electronic Devices, to keep them within permitted operating temperature limits. Heat indulgence techniques include heat sinks, fans for air cooling, and other forms of cooling such as liquid cooling. Heat produced by electronic devices and circuitry must be self-indulgent to improve reliability and prevent premature failure. Integrated circuits such as CPUs, chipset, graphic cards, and hard disk drives are susceptible to temporary malfunction or permanent failure if overheated. As a result, efficient cooling of electronic devices remains a challenge in thermal engineering. Heat sinks are commonly used for cooling of electronic devicesHeat sinks, an array of heat fins, remove the heat from the surfaces of the chips by enhancing the heat Transfer rate through heat conduction process.