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The purpose of this study is to obtain some information about the viscoelastic properties of the material and to see the effect of the addition of plasticizer on these properties. In particular, we try to study the loss of plasticizer, caused by ageing under conditions of utilization, on the properties of material at the neighborhood of vitreous transition.

Using a viscoelastimeter, the study of a polyamide-11 (PA11) at the neighborhood of its temperature of vitreous transition Tv has shown that the increase of the plasticizer rate clearly improves the properties of the material by decreasing its Tv temperature. The comparison of the curves giving the modulus of elasticity E' of the various samples showed that the mechanical properties of the material improve with the increase of the concentration of plasticizer, but ageing reduces this improvement by causing the loss of plasticizer, thus, the temperature range of utilization of material is reduced.

Polyethylene (PE) film was coated with nanosilica-polyamide layer using rod Mayer process. The nanosilica-polyamide system was prepared by dispersing nanosilica (nano-SiO₂) powder into solvent borne polyamide binder under vigorous stirring. Various compositions of nanosilica-polyamide slurry were prepared. The thickness of the layer was about four µm and eight µm for single and double layer coating respectively. A battery of characterization procedures were used to study the properties of the nanocomposite coating. The uniformity of silica dispersion was probed using elemental mapping procedure and scanning electron microscopy (SEM). With the introduction of nanosilica to polyamide binder, the visible light transmittance and ultra-violet (UV) radiation of nanosilica-polyamide system reduced with increasing nanosilica content and coating layer thickness. Infrared (IR) effectiveness (between 7 µm to 13 µm wavelengths) measurements by FTIR also showed that nanosilica-polyamide system coating on PE film surface greatly improved the thermic effect of PE film. The nanocomposite coating containing 14 wt% nanosilica and with eight µm coating thickness has improved the IR effectiveness of PE to 76%. Thermic effect of the nanocomposite increased with increasing nanosilica content and coating thickness.

Recent advances in polymer nanocomposites open a wide range of applications in various industrial sectors. Due to their high potential properties, these materials are replacing the usage of metals for many heavier components in automobile industries. In this experimental work, the tribological performance of Graphene oxide (GO) — Polyamide is investigated against pristine polyamide by fabricating gears for the usage in engineering applications. A gear test rig was developed in-house for analysis to study the specific wear rate and temperature gradient at different conditions of load and speeds. The wear resistance of the polyamide gears with the addition of 0.03wt.% of graphene oxide is better than the pristine polyamide gears and the specific wear rate is reduced significantly. The reduced specific wear rate of these polymer nanocomposite gears is attributed to the superior properties of graphene oxide such as High specific surface area, good adhesion properties and enhanced glass transition temperatures. The GO nanocomposite gear seems to be a potential alternative against conventional gears for engineering applications. Finally, the wear mechanisms and the potential of GO-based polyamide nanocomposite gears were proposed tentatively in the development of transmission gears for engineering applications.

This prospective non-randomised two-cohort study compares the use of an absorbable suture (Poliglecrapone [Monocryl]: Group A) and a non-absorbable suture (Polyamide [Ethilon]: Group B) in wound closure after elective carpal tunnel decompression. The primary outcome was scar cosmesis as assessed by the Stonybrook Scar Evaluation Scale (SBSES); the financial cost of wound closure was compared as a secondary outocome. All fifty patients completed follow-up. At six weeks, there was no significant difference in the two groups regarding scar tenderness (p = 0.5), although residual swelling was more evident in the absorbable group (p = 0.2). The mean SBSES score at six weeks was 4.72 in Group A, and 4.8 in Group B (p = 0.3). The unit cost per closed wound of Monocryl was three times than Ethilon (p < 0.05). Ethilon is thus cost-effective without compromising the cosmetic outcome, and we recommend using this as the preferred suture for closure of carpal tunnel wounds.

20 wt% polyamide 12 (PA1212) pellets were dissolved in molten caprolactam. The caprolactam was then catalyzed at 180°C and polymerized by means of anionic ring-opening polymerization to produce in situ blends of the resultant polyamide 6 (PA6) and PA1212. Mechanical blends with same ingredient were prepared through melt blending on a twin-screw extruder. Scanning electron microscopy (SEM) observation revealed that contrary to the mechanical blends with small spherulites embedded in the matrix, no phase-separation existed in the in situ blends. The results of thermal analysis by differential scanning calorimetry (DSC) showed that single melting peak and crystallization peak existed for the in situ blends, while two melting and crystallization peaks appeared for the mechanical blends. The in situ blend film and the mixed blend film, both cast from a dilute formic acid solution with a concentration of 0.5 g/L, remained similar crystallization and melting behavior as above. It is proved by solution ¹³C-NMR analysis that transamidation took place during the in situ blending, and it is suggested that the combination of temperature increasing and the basic surrounding derived from NaOH during polymerization resulted in the occurrence of transamidation. Furthermore, it is proposed that the interchange reaction between PA1212 and PA6 also resulted from the degradative reaction during the anionic polymerization.

A new polymer, poly(imino isophthaloyl imino (2,4,8,10-tetraoksoaspiro [5,5] undekan-3,9-dipropylene)) [poly(IPIT)] was synthesized by an interfacial polycondensation reaction. The characterization of poly(IPIT) was conducted by using FT-IR, ¹³C-NMR, TG and DTA techniques. The kinetics of the thermal degradation of poly(IPIT) was investigated by thermogravimetric analysis at different heating rates. TG curves showed that the thermal decomposition of poly(IPIT) occurred in three stages. The apparent activation energies of thermal decomposition for poly(IPIT), as determined by the Tang method (TM), the Flynn-Wall-Ozawa method (FWO) and the Kissinger-Akahira-Sunose method (KAS) are 58.09, 57.7 and 61.0 kJ/mol for the first stage decomposition, 106.1, 105.6 and 109.8 kJ/mol for the second stage decomposition, and 138.1, 137.5 and 141.4 kJ/mol for the third stage decomposition, respectively.

The main objective of this laboratory project is to investigate the effectiveness of using polyamide grout injection on sand improvement. Soil samples with different dry densities in their loose, medium and dense state (cylindrical shaped) with 5cm diameter and 10cm height are subjected to polyamide injection. In order to investigate the grout injection effect on soil's strength, the specimens are subjected to one dimensional unconfined compression tests. We know that polyamide doesn't mix with water and we should mix it with citric acid. It has been observed that by increasing the polymer percent in polymer-water-citric acid mixture grout, the soil compressive strength and elastic modulus has been improved significantly. In general denser sands presented higher compressive strength and elastic modulus in comparison with looser ones in same polymer percents.