The contents of EU rubber, extracted from leaves of Eucommia ulmoides, were determined by the gravimetric method, and the molecular-weight and molecular-weight distribution
were determined by gel permeation chromatography (GPC).
Its molecular weight is slightly higher than standard PS, and it has a much broader molecular-weight distribution
log G" plot is independent of the molecular weight, the short-branch length, and the testing temperature, it depends strongly on the molecular-weight distribution
, and the degree of long-chain branching and its distribution (8).
PHA has a narrow molecular-weight distribution
(which can be fine-tuned) and good printability.
The narrow molecular-weight distribution
and broad crystallinity distribution of Versify copolymers result in improved temperature performance over that of similar metallocene products.
Basell has two new grades of Metocene mPP homopolymers for injection molding, both of which are nucleated and have very narrow molecular-weight distribution
. They are said to provide low warpage, high clarity, good stiffness, and high flow (achieved in the reactor without "visbreaking").
The "super-strength" resins have a narrower molecular-weight distribution
and more homogeneous short-chain branching distribution than the conventional hexene resins, leading to a lower elasticity and less orientation in the film, and a lower concentration of lower-molecular weight species for improved film blocking.
The effect is temporary and is accomplished without additives, change in molecular-weight distribution
, or any performance tradeoff, says Coperion.
Moreover, the molecular-weight distribution
of the starting resin is more closely preserved because of reduced chain scission during the functionalization reaction, according to Crompton research fellow William Sigworth.
Irgatec CR 76 is a non-peroxide modifier that provides controlled degradation of a low-MFR PP into a high-flow resin with narrow molecular-weight distribution
. It allows a spunbond grade of 20 to 35 MFR or recycled fiber scrap to be used in melt-blown applications, which require higher flow.
LDPE isn't often MD oriented because its broad molecular-weight distribution
gives it too little tensile strength.
Versify polymers have narrow molecular-weight distribution
but broad composition and crystallinity distribution, which is said to result in improved heat resistance compared with metallocone-based products of comparable olefin content.