Why fibres are strong only in one direction? [closed]








**Closed.** This question is [off-topic](/help/closed-questions). It is not currently accepting answers.
 
 






---








 **Homework questions** must demonstrate some effort to understand the underlying concepts. For help asking a good homework question, see: [How do I ask homework questions on Chemistry Stack Exchange?](https://chemistry.meta.stackexchange.com/questions/141/how-do-i-ask-homework-questions-on-chemistry-stack-exchange)




Closed 3 years ago.








[Improve this question](/posts/127373/edit) 



Why fibres are strong only in the direction they are oriented?Why they break if we pull at right angle to their orientation?


[![enter image description here](https://i.stack.imgur.com/heREl.gif)](https://i.stack.imgur.com/heREl.gif)


Here each blue line represents combination of polymeric chains.




Fibres are made of long linear molecules, in which the atoms are bound by covalences C-C or C-O. Usually it is a long C-C-C-C-C-C-O-C-C-C, with one O from time to time. Such bonds are hard to break. But paralleled fibres are hold together by van der Wals forces, which are rather weak. They are not difficult to get separated. That is why a fiber can be easily split in two in the sense of the length, and only in this sense.


 2