5 Answers

Kia,   leave her alone .  As long as the bad blood between the two of you isn't getting in the way of you and your grandchildren having a relationship, let her stew in her own bile.

If you know or want to know why she has bad feelings about you, try to set a time when the two of you can talk. If you get to do this, you need to listen and say absolutely nothing.  Let her vent.  DO NOT come back at her with anything remotely related to, "Well, if YOU..." 
If she asks you a direct question (vs. a rhetorical), tell her you would like some time to compose your answer (off the top of my head is never a good place to find an answer).
You can tell her you are really unhappy about the bad relationship you have and are anxious to resolve any issues she has about you. 

LISTEN AND HEAR what she says.  Take everything seriously, even if it sounds ridiculous. Report back here with some details, so we can help you with better advice.  The first step is to get her talking and find out what's going on with her.

If the things she is doing and saying are dangerous and/or could harm her or her children (or you or anyone else), contact "the authorities".  Be very careful if you do this.  She could have the children removed from her home and you two will never speak again.

Leave her alone...

I would be keeping an eye on her,how long has this behaviour been going on ?If her moods are totally out of charactor she may be suffering an mental illness or it could be the affects of drugs.Try and refrain from arguing with her as this will only set her off more so.Meet up with her so you can asess the situation whilst she is in your company.If on the other hand your relationship has been strained over the years,she may have bottled up feelings towards you,and is starting to vent her anger,all you can do is be there for her and talk through her problems.

If  she hate s you that bad  speak softly but carry a big stick   just in case

There's nothing more to add as the first answers would fit the bill. I know she is your daughter but there comes a point that one must back away and stop instigating the problems by pushing. When you think of your daughter send her light and love and let her go for now.