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Deconvolution of Molecular Weight Distribution of XCAT™ VP-100 PE Products

IP.com Disclosure Number: IPCOM000244739D
Publication Date: 2016-Jan-06
Document File: 2 page(s) / 45K

Publishing Venue

The IP.com Prior Art Database

Abstract

A new methodology was developed with GPC-IR to deconvolute the molecular weight distribution (MWD) of XCAT™ VP-100 PE products into two components: homopolymer PE and copolymer PE. The individual MWD of each component, the comonomer content in the copolymer and the copolymer mass fraction in the product can all be obtained.

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DESCRIPTIVE TITLE:


Deconvolution of Molecular Weight Distribution of XCAT™ VP-100 PE Products

ABSTRACT:


A new methodology was developed with GPC-IR to deconvolute the molecular weight distribution (MWD) of XCAT™ VP-100 PE products into two components: homopolymer PE and copolymer PE. The individual MWD of each component, the comonomer content in the copolymer and the copolymer mass fraction in the product can all be obtained.

Describe the invention on the following pages.


1. Problem to be solved?

The XCAT™ VP-100 Metallocene Catalyst (available from Univation Technologies, LLC, Houston, TX) products generally include two components: the homopolymer PE and the copolymer PE or the Poly(Ethylene-co-Hexene) (EH), a fact that is revealed by polymer fractionation technique TREF and CFC. However the individual MWD and the comonomercomposition (CC) for each componentcannot be directly obtained from any of the current techniques including TREF, CFC, GPC-IR, and the combination of PREP with GPC-IR. TREF doesn't provide MW information; CFC provides MW in a qualitative fashion because MW calculation depends on CC of the copolymer which is unavailable; GPC-IR provides both MW and CC accurately, but this information is about the whole sample instead of the individual components. The PREP fractionates the sample based on MW or composition. If combined with GPC-IR, the MW and CC for each fraction can be further measured. However, the information obtained in this way is not about two polymer components but multiple fractions in which the two components are still convoluted. In addition, it usually takes several days to get one sample fractionated with PREP.


2. How is the problem solved?

The deconvolution of GPC chromatogram is based on several assumptions and some mathematical relationship about the mass fraction and comonomer composition. The assumptions include: a) polymer molecules in dilute solution don't interfere with each other and they coelute independently; b) there is only one type of copolymer with single comonomer composition c) copolymer PE is dominant in high MW end and elute earlier than homopolymer PE. The first assumption is self-evident, the second assumption has been validated with TREF and the third assumption has been validated with CFC technique (see figure 1). The assumption b) and c) are the key aspects towards the success of this method.


3. Detailed description of the invention and data or examples.

One of VP-100 samples has been tested with TREF and GPC-IR. Figure 1a shows the TREF data of the VP-100 sample EXT828, which clearly indicates about the sample is bi...