This technique has been used to produce a variety of structures, including simple multi-arm star macromolecules with arms of identical chain length and composition (
refs. 10, 36 and 37) and star polymers with arm asymmetry in length and/or composition (
refs.
These two samples were submitted as part of an ASTM study on definitive testing of natural robber (
ref. 10).
Toyota has demonstrated that significant improvements in the mechanical properties of nylon can be achieved in this manner (
ref. 4).
A density of 1.14 g/[cm.sup.3] for these rubbers was previously reported (
ref. 8).
A previous work (
ref. 20) compared the micro IRHD and micro durometer instruments, looking at the effects of sample thickness, lateral dimensions, bent samples, temperature, retesting a previously measured spot and the effect of the foot force on the type M durometer.
Afterwards, the molded parts were submitted to a standard tensile test (
refs. 3, 20 and 21) in order to check the adhesion strength.
These compounds reduce surface polarity, and some can chemically bind filler to polymer (
ref. 1).
Since chain transfer preferentially occurs with large molecules, a branched molecule becomes more branched (
ref. 3), generating gigantic molecules, macro-gel.
Literature reports of efficiencies between 800 and 8,000 g polymer per g vanadium possibly understate the latest developments with vanadium systems; however, it is generally accepted that significantly higher polymer yields are achieved with titanium (
ref. 8).
He had previously worked on block copolymers produced by difunctional initiation (
ref. 9) and he soon made an S-B diblock polymer of about 14% styrene content.
The most general strain energy function (excluding finite compressibility) proposed by Rivlin (
ref. 1) is:
This empirical relationship sometimes works quite well; however, it does not have a theoretical basis, therefore it may not always work (
ref. 23).