[Blake Mumford]

Dear sir/ma'am,

I'm doing an extended experimental investigation on exposing certain polymers to heat. I know that polymers are generally sorted into two groups: thermoplastics or thermosetting plastics. What I can't seem to find out is what are the differences in chemical structure and bonding that determine whether a polymer is a thermoset or a thermoplastic.

The polymers I investigated were Polyurethane, HDPE, Acrylic and PVA.

Thankyou in advance,

Blake

[Borek]

Please read forum rules.

[Blake Mumford]

Please be more specific than: "please read forum rules." I already have multiple times. I cannot see where I may have violated any of your rules. Please specify what the problem is and I will seek to rectify it.

[Borek]

What about points 2 and 4? You have posted 5 questions in separate threads (deleted now). In no one you have signalled that you did any effort to find out the answer.

[Blake Mumford]

Thankyou for taking the extra 30 seconds of your life to clarify that issue. Given that I spent quite a lot more time writing up the questions I thought you could of at least spared me 30 seconds of your time. As to point two if you actually read and comprehended what it was saying you'd find I did not in fact break this rule. Direct quote verbatim:

"Please don't list 5-6 homework questions and say you need help right away. It is your own responsibility to start your homework early.  If you do have a lot of questions put them in one post but don't expect them to all be answered at once."

True I listed 5 questions. My defense is as follows:

1) They were not homework questions which you would have noticed had you actually took the time to read the questions. It was an extended experimental investigation. Extended being the key word.

2) I started 3 weeks ago.

3) As for putting them all in the one post: Had I put all questions in the same thread I would be violating rule 1. Direct quote verbatim: " Please have your subject-title relating to the question you need help with." True I could have called the thread: Physical and Chemical properties of polymers. But this would be as bad as having a title as: Chemical structure or Properties of metals. Calling it "Physical and Chemical properties of polymers" would be a far too general statement. Thus I decided 5 separate threads would be more appropriate. Looking at the titles of other threads I cannot see how mine was any worse of an offense.

4) I don't seem to recall making any demand that you help me immediately. As it states "don't list 5-6 homework questions AND say you need help right away". The term "and" suggests that both parts of this statement must be true in order for me to violate this rule. As I did not ask for help immediately point two has no relevance to my situation.

Again had you read point four you would have realised that my conduct was not incorrect in anyway. If you read what I wrote I did in fact make an attempt to answer the questions. This point is open to interpretation anyway.

Again thankyou for your precious time. I know I won't waste mine here again.

[Donaldson Tan]

Checked out Wikipedia.

http://en.wikipedia.org/wiki/Thermoplastic
http://en.wikipedia.org/wiki/Thermosetting_plastics

The difference between thermoplastic and thermosetting plastic is their response to heat.

Thermosetting plastic changes its structure by formation of covalent bonds for cross-linkage of polymer chains upon heating beyond a critical temperature. Thermoplastic are just polymer chains bonded together via very extensive Van Der Waals' forces (VDWF). The VDWF are easily overcome by heat, thus the thermoplastic "melts"

[Donaldson Tan]

4) I don't seem to recall making any demand that you help me immediately. As it states "don't list 5-6 homework questions AND say you need help right away". The term "and" suggests that both parts of this statement must be true in order for me to violate this rule. As I did not ask for help immediately point two has no relevance to my situation.

The gist of it is that this forum is ethically against doing homework questions as opposed to teaching forum members on how to do their homework. Sometimes, it is hard to differentiate homework questions from genuine conceptual challenges faced by the thread-starter. Different mod/admin has their individual rule of thumb to decide. No doubt this is open to intepretation, but it is this convenience that allow this forum to become a very extensive chemistry forum. On the bright side, this thread of yours is not locked or deleted, so other forum members or staff can post their answers to aid you. You were only warned.