Poly butene parameter

It was noted also that satisfactory compatibilization could be achieved by local miscibility (given by solubility parameters) rather than direct matching of the chemical and macro-molecular composition. This may require the copolymer to have several components, such as poly(styrene-co-ethylene)-b-poly(butene-co-styrene) (SEES), which has been found useful in compatibilization of HDPE and PET (Bonner and Hope, 1993). 

Table 5-6. Thermodynamic Parameters for the Three Modifications of it-Poly (butene-1)...

The nonisothermal crystallization process of isotactic poly(butene-l) as a function of cooling rate was investigated by Silvestre et al. [77]. The samples were melted at 160°C for ten minutes and cooled to room temperature at different rates 0.5, 1, 2 and 4°C/min. The induction time and the time required for the completion of the phase transition were found to decrease with cooling rate. The calculated CRC parameter was 18 h. ... 

Liu and Zhong introduced a number of QSPR models based on molecular connectivity indices [151, 152], In a first iteration, the researchers developed polymer-dependent correlations descriptors were calculated for a set of solvents and models were developed per polymer type [151], Polymer classes under consideration were polystyrene, polyethylene, poly-1-butene, poly-l-pentene, poly(4-methyl-l-pentene), polydimethylsiloxane, and polyisobutylene. As the authors fail to provide any validation for their models, it is difficult to asses their predictive power. In a subsequent iteration and general expansion of this study, mixed and therefore more general models based on the calculated connectivity indices of both solvent and polymers were developed. While it is unclear from the paper which polymer representation was used for the calculation of the connectivity indices, the best regression model (eight parameter model) yields only acceptable predictive power (R = 0.77, = 0.77, s = 34.47 for the training set, R = 0.75... 

The principal polyolefins are low-density polyethylene (ldpe), high-density polyethylene (hope), linear low-density polyethylene (lldpe), polypropylene (PP), polyisobutylene (PIB), poly-1-butene (PB), copolymers of ethylene and propylene (EP), and proprietary copolymers of ethylene and alpha olefins. Since all these polymers are aliphatic hydrocarbons, the amorphous polymers are soluble in aliphatic hydrocarbon solvents with similar solubility parameters. Like other alkanes, they are resistant to attack by most ionic and most polar chemicals their usual reactions are limited to combustion, chemical oxidation, chlorination, nitration, and free-radical reactions. 

LCT (originally developed for di-block copolymers) was found to be particularly useful to explain miscibility of polyolefin blends where the two resins differ in the type and size of short chain branching. The stractural units of a polymer with two carbons in the main chain can be written as PE = (CH,-CH,), PP = [CH,-CH (CHj)], poly-2-butene (P2B) = [CH (CH3)-CH (CHj)], PIB = [CH -C (CHj) ]jj, poly(4,4-dimethyl 1-butene) (PDMB) = [CH -CH (C Hg)], etc. Three structural parameters (ratio of end to interior groups) have been used to distinguish PO structure r, p, and q. Their values for the model macromolecules discussed above are listed in Table 2.7. 

Table 1. Solubility parameter of poly(l-butene), isotactie. ...

Solubility parameter of poly[styrene-b-(l-butene-eo-ethylene)-b-styrene]... 

Figure 12 shows the results for the modeling of the solubility of the copolymer poly(ethylene-co-l-butene) in propane. The pure-component parameters for poly (ethylene) (HOPE), poly(l-butene), and propane as well as the binary parameters for HDPE/propane and poly(l-butene)/propane were used as determined for the homopolymer systems. 

TABLE 9 Basic Parameters for the Nucleation and Crystallization of Isotactic Poly(1-butene) ... 

Poly(l-butene) exists in three different helical conformations in the solid state [34] (Fig. 9.11). The CP-MAS spectra of the three crystalline polymorphs and the amorphous polymer of poly(l-butene) (Fig. 9.12) have been reported, and the spectra were interpreted by using a y-gauche shielding parameter that is dependent on the dihedral angle. The y-gauche shielding parameter is reduced to half its standard value when the angle is increased to 82 1°. 

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