Question

In: Mechanical Engineering

How does polymeric glass formation prevent flow of linear polymer? Explain Tg and chemical reasons. How...

How does polymeric glass formation prevent flow of linear polymer? Explain Tg and chemical reasons. How does this prevention of flow effect mechanical charcteristics?

Solutions

Expert Solution

Polymer glass formation occurs at certain specified temperature for a given polymer and this transformation occurs without the formation of crystal solids through a process called glass transition. These transition into solids prevents the flow of linear polyme that lacks branching and dendritic structure and chains.

Glass transition temperature is the gradual and reversible transition in amorphous , non crystalline material from a relatively hard and brittle state to soft and viscous state.

Its prevention affects the mechanical properties in several ways :-

1. The material exhibits a step in thermal expansion coefficient and specific heat.

2. No phase change occurs and material becomes more viscous and semisolid in nature.

3. The stiffness of the polymers is also decreased as the glass transition temperature is reached.


Related Solutions

define the glass transition temperature of a polymer , explain the difference in the glass transition...
define the glass transition temperature of a polymer , explain the difference in the glass transition temperature values between polystyrene (Tg = 100degrees celcius) and polyethylene (Tg = -20 degrees celcius)
1.How does the chemical structure of a Phospholipid lead to the formation of a membrane as...
1.How does the chemical structure of a Phospholipid lead to the formation of a membrane as seen in the cell? Why is this structure semi-permeable?   Prokaryotes have no membrane-bound organelles. Why does the organelle membrane matter?
Briefly describe the Munch pressure flow hypothesis. How does polymer trapping fit into this scenario?
Briefly describe the Munch pressure flow hypothesis. How does polymer trapping fit into this scenario?
Explain why the melting and glass transition temperatures of a polymer depend on its molecular weight....
Explain why the melting and glass transition temperatures of a polymer depend on its molecular weight. Your answer should include reference to free volume theory. (12)
How is glycogen synthesis and breakdown a) reciprocally regulated to prevent the formation fo a futile...
How is glycogen synthesis and breakdown a) reciprocally regulated to prevent the formation fo a futile cycle? and b) hormonally regulated to increase the supply of available ATP during times of stress?
Week 12 1. Explain 2 reasons for the formation of corporate subsidiaries. 2. Identify four reasons...
Week 12 1. Explain 2 reasons for the formation of corporate subsidiaries. 2. Identify four reasons for the formation of foreign subsidiaries. 3. Why is Amazon considering foreign subsidiaries in Europe as a management strategy?   4. Explain two reasons why Vodafone and Verizon talked about an acquisition. Which company was acquired and what was the cost? Was this strategy of acquisition positive or negative? 5. Why did Google acquire Android? Explain why it was a good acquisition for Google.
explain reasons for the pay gap; discuss the glass ceiling and sexual harassment in the workplace....
explain reasons for the pay gap; discuss the glass ceiling and sexual harassment in the workplace. Is it getting better or worse? what can be done?
how does Alesse works to prevent pregnancy?
how does Alesse works to prevent pregnancy?
briefly explain on a fundamental chemical basis what effect adding charges has on the polymer chain...
briefly explain on a fundamental chemical basis what effect adding charges has on the polymer chain and how this relates to polarons and charge transport within the organic material. Then describe three different methods or devices through which charge carriers are added to an OSC, the main purpose or function of each
How does TCP prevent sender from overflowing the receiver’s buffer? Explain how to calculate rwnd at...
How does TCP prevent sender from overflowing the receiver’s buffer? Explain how to calculate rwnd at sender side and its relationship with LastByteSent and LastByteAcked.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT