Polymer Testing 

About: Polymer Testing is an academic journal published by Elsevier BV. The journal publishes majorly in the area(s): Materials science & Ultimate tensile strength. It has an ISSN identifier of 0142-9418. It is also open access. Over the lifetime, 5962 publications have been published receiving 145510 citations.

Ftir studies of -phase crystal formation in stretched pvdf films

Abstract: Poly vinylidene fluoride (PVDF) is a semi-crystalline polymer which shows polymorphism and is commonly crystallized in non-polar crystalline α-phase. It has found various applications during the last decades and the most important applications lies in its pyro- and piezoelectric properties. The β-phase content is of prime importance in these applications so that increasing β-phase content of the polymer has always been of great concern in this field. Calorimetric studies and FTIR spectra show the appearance of β-phase in compression molded films of two different grades of PVDF resin. β-phase formation is more evident in stretched films by a transformation mechanism of α to β-phase via the formation of a necking region during stretching. By using FTIR techniques, a maximum content of 74% for β-phase was calculated. This was achieved during stretching at 90 °C and for a stretch ratio between 4.5 and 5. FTIR spectra offer a precise method for detecting the variations of β-phase in polymer films.

Biopolymers: overview of several properties and consequences on their applications.

Abstract: Recently, interest in composite manufacturing has shifted towards the use of natural fibres as reinforcement because of their environmental benefits. The use of a biodegradable matrix is worth considering since this would result in a completely biodegradable composite. In order to assess the most suitable matrix polymer, one must know the properties of the available polymers. Since data tend to be widely scattered over many sources and are very scarce compared to the conventional polymers, it is the purpose of this article to give an overview of the most relevant properties of a range of biodegradable polymers. An overview such as the one given here may provide a useful guide in establishing the best compromise between conflicting property demands. Data are presented mostly as ranges (in tables) as well as in graphs for quick comparison reasons. One specific application (thermoplastic pultrusion with flax as reinforcement) is also studied.

Polyethylene characterization by FTIR

Abstract: Important experimental parameters for FTIR spectra acquisition were studied: apodization, beam aperture, number of scans and spectral resolution, using polyethylene samples. The optimum conditions for the analyses were established and permitted unequivocally to identify the three most important commercially available grades: low density, high density and linear low density products (LDPE, HDPE and LLDPE respectively).

FDM process parameters influence over the mechanical properties of polymer specimens: A review

Abstract: Designing and manufacturing functional parts for fields such as engineering and medicine is a major goal of Fused Deposition Modeling (FDM). These activities should be supported by knowledge on how different settings of process parameters impact the mechanical behavior of the products. However, obtaining this information is a quite complex task given the large variety of possible combinations of materials-3D printers-slicing software-process parameters. Thus, the importance of reviewing the current research on this topic for identifying practical and useful aspects, key process parameters and limitations, but also for understanding to what extent the results of these researches are relevant and can be applied in further studies and real applications. A systematic literature search was performed based on classification according to the type of 3D printing polymer. The most significant process parameters considered as influencing FDM specimens' tensile, compression, flexural or impact strengths are discussed considering the results presented in the literature. A necessary distinction between the mechanical properties of material and testing specimens (as given by producers and by experiments) and the mechanical behavior of a FDM end-part is also made.

DSC isothermal polymer crystallization kinetics measurements and the use of the Avrami equation to fit the data: Guidelines to avoid common problems

Abstract: In this paper we offer guidelines to adequately fit isothermal polymer crystallization kinetics data obtained by differential scanning calorimetry (DSC) employing the widely used Avrami equation. A methodology on how the experimental DSC data should be measured and later analyzed in order to minimize the possible errors associated with data manipulation is provided by a thorough evaluation of: (i) the determination of the onset of crystallization or induction time, (ii) the establishment of the baseline and incomplete isothermal crystallization data, (iii) the effect of the cooling rate from the melt to the isothermal crystallization temperature and (iv) the conversion range employed for the fitting. Therefore, this paper provides a practical guide to the fitting of the Avrami equation along with error assessments.