Structure changes in PVC at high temperatures as determined from X-ray diffractometer curves

The gelation of PVC: Characterization and control

“…It soon became obvious that the consistency of the gels varied according to the type of solvent. This is shown very clearly in a plot of gel modulus versus solubility parameter ( 6 ) (Fig. 1).…”

“…The concept of the solubility parameter in polymer-solvent systems implies that good solvents for a given polymer are those that have the same 6 value as the polymer is question. The greater the difference in 6 values, the worse a solvent becomes with respect to that polymer. The 6 value for PVC is 9.6 [ 51.…”

4D Printing of Polyvinyl Chloride (PVC): A Detailed Analysis of Microstructure, Programming, and Shape Memory Performance

“…[59] It has been reported that the intensity of the peak about 2𝜃 = 25°is higher than that of about 17°by almost 1.3:1 ratio in the original XRD spectrum of PVC's crystallites. [36,57] Despite the mentioned fact, molecular orientation seems to make this trend the opposite, yielding the peak of about 17°as the most prominent due to the possible formation of the mesomorph phase with an intermediate level of an order. [35,37,56] Furthermore, molecular orientation modifies the unit cell by raising the intensity of the 200 plane peak compared to the 110 and makes their difference the least, as it is recognized for 3D printed PVC regarding the spectrum shown in Figure 6.…”

“…This phase is made by parallel molecular arrangement like the nematic structure in 5 to 5.4 Å distance between PVC chains, which is stipulated by a broad hump with a maximum of about 2𝜃 = 17.5. [37,54,56] Guerrero et al [57] conducted an XRD examination on a heated PVC to assure that there is no crystallite and obtained a double hump curve with maximums at 2𝜃 = 16 and 23.2 such that the second hump was smaller than the first hump. The mentioned spectrum has a good resemblance to Figure 6 curves obtained for the present study.…”

X‐ray pole figures to assess orientation in PVC sheets

“…1 The polymer chain axis lies in the c direction, so is parallel to (200) and (110) planes. The broad peak around 2582y consists of three overlapping reflections as indicated; Guerrero et al 13 showed that the relative intensity of these peaks was as follows, I (210) : I (201) : I (111) is 34.4 : 72.7 : 66.9 (relative values calculated on an arbitrary scale), so that this peak is primarily derived from planes which are not parallel to the chain axes (i.e., c direction).…”