Light Microscopy Measurements Research Articles

Synthesis, chiral separation and physical properties of the cinnamic acid derivatives exhibiting short-pitch cholesteric and TGB phases

ABSTRACT Two new photosensitive chiral liquid crystalline materials derived from cinnamic acid were synthesised in (R) and (S) enantiomer forms. The materials were characterised by NMR spectroscopy, purified by preparative liquid chromatography, and the chemical purity of the final products was determined by high performance liquid chromatography (HPLC). High optical purity was reached for all enantiomers. The enantiomer elution order was confirmed by the analysis of non-racemic (R) and (S) mixed samples. The cinnamic acid derivatives are capable of undergoing photoisomerisation. Sample irradiation was performed to realise E-Z isomerisation and investigate its effect on the enantioseparation. The conditions of the enantioselective HPLC method were optimised to achieve a baseline separation for all studied materials both before and after irradiation by the UV light. The mesogenic properties of the studied enantiomers and their racemic mixtures were obtained from differential scanning calorimetry measurements, optical textures observed under the polarising light microscope and X-ray diffraction measurements. Cholesteric and TGB phases have been found for the enantiomers and, analogously, nematic and smectic phases have been confirmed for their racemates. The temperature dependence of the optical birefringence has been studied for the racemates in the temperature range of the mesophases.

On the Optical Assessment of the Structural Degradation of Rheologically Stressed Lubricating Greases

This work explores optical measurements' potential to better understand structural degradation due to the internal friction process of lubricating greases. The samples have been examined as closely as possible to their original state due to the specimen preparation protocol. Eleven model lubricating greases were evaluated for these purposes. Image analysis of transmitted light microscope, SEM and AFM measurements were used to evaluate the grease microstructure under stressed and unperturbed conditions. The results showed that the type of thickener could significantly influence the internal frictional energy due to the structural degradation of the lubricating grease. Thus, the structural skeletons of lithium and calcium greases can dissipate less mechanical energy during a shearing process than polyurea grease or isolated pure biogenic greases.

Macroscopic and microscopic comparison of pecten oculi in different avian species.

The current study aims to present differences between the pecten oculi of different avian species through morphologic, macroscopic, light, and electron microscopic examinations. The study is a comprehensive research on seven avian species (sparrowhawk, hawk, magpie, swan, heron, pheasant, duck). The right eyes of the animals utilized in the study were removed for light microscopic examination, whereas their left eyes were removed for electron microscopic and macroscopic examinations. Morphometric analyses, as well as stereo and light microscopic measurements, were carried out on the pecten oculi of the animals. Given all these data, it was determined that the height of the pecten oculi did not differ among the species in the study; however, the pecten oculi were larger in birds with the highest value compared to the other species in the macroscopic measurements. Also, the pecten oculi vessels were larger, and the number of melanocytes was higher in keen eyesight, raptor, and migratory birds with large bulbus oculi. All these data suggest that the pecten oculi not only supplies nutrient to the retina but also contributes to sharp vision during migration and hunting, UV absorption from sunlight, as well as preservation of intraocular equilibrium.

Detailed analysis of a room temperature antiferroelectric liquid crystalline material forming polar mesophases

Liquid crystalline materials possess the ordering of a crystal and fluidity of the liquid to varying extents. They exhibit strong anisotropic properties, which make them a technologically desirable substance. In this paper, we investigated a chiral semi-fluorinated 4-{[(2S)-octan-2-yloxy]carbonyl}phenyl-4′-({6-[(2,2,3,3,4,4,4-heptafluorobutanoyl)oxy]hexyl}oxy)-[1,1′-biphenyl]-4-carboxylate (abbr. 3F6Bi) material. The charge dynamics, electrical and nonlinear properties, and spin-orbit delocalizations are investigated through DFT calculations. The polarized light microscopic measurements highlight three polar smectic phases of the compound. The dielectric biaxiality and relaxation processes are probed in the low-frequency regime. The spontaneous polarization, response time, and rotational viscosity are calculated via the reverse field technique.

Horizontal Hippocampal Slices of the Mouse Brain.

The hippocampus is a highly organized structure in the brain that is a part of the limbic system and is involved in memory formation and consolidation as well as the manifestation of severe brain disorders, including Alzheimer's disease and epilepsy. The hippocampus receives a high degree of intra- and inter-connectivity, securing a proper communication with internal and external brain structures. This connectivity is accomplished via different informational flows in the form of fiber pathways. Brain slices are a frequently used methodology when exploring neurophysiological functions of the hippocampus. Hippocampal brain slices can be used for several different applications, including electrophysiological recordings, light microscopic measurements as well as several molecular biological and histochemical techniques. Therefore, brain slices represent an ideal model system to assess protein functions, to investigate pathophysiological processes involved in neurological disorders as well as for drug discovery purposes. There exist several different ways of slice preparations. Brain slice preparations with a vibratome allow a better preservation of the tissue structure and guarantee a sufficient oxygen supply during slicing, which present advantages over the traditional use of a tissue chopper. Moreover, different cutting planes can be applied for vibratome brain slice preparations. Here, a detailed protocol for a successful preparation of vibratome-cut horizontal hippocampal slices of mouse brains is provided. In contrast to other slice preparations, horizontal slicing allows to keep the fibers of the hippocampal input path (perforant path) in a fully intact state within a slice, which facilitates the investigation of entorhinal-hippocampal interactions. Here, we provide a thorough protocol for the dissection, extraction, and acute horizontal slicing of the murine brain, and discuss challenges and potential pitfalls of this technique. Finally, we will show some examples for the use of brain slices in further applications.

Posterior thalamic nucleus axon terminals have different structure and functional impact in the motor and somatosensory vibrissal cortices

Rodents extract information about nearby objects from the movement of their whiskers through dynamic computations that are carried out by a network of forebrain structures that includes the thalamus and the primary sensory (S1BF) and motor (M1wk) whisker cortices. The posterior nucleus (Po), a higher order thalamic nucleus, is a key hub of this network, receiving cortical and brainstem sensory inputs and innervating both motor and sensory whisker-related cortical areas. In a recent study in rats, we showed that Po inputs differently impact sensory processing in S1BF and M1wk. Here, in C57BL/6 mice, we measured Po synaptic bouton layer distribution and size, compared cortical unit response latencies to “in vivo” Po activation, and pharmacologically examined the glutamatergic receptor mechanisms involved. We found that, in S1BF, a large majority (56%) of Po axon varicosities are located in layer (L)5a and only 12% in L2–L4, whereas in M1wk this proportion is inverted to 18% and 55%, respectively. Light and electron microscopic measurements showed that Po synaptic boutons in M1wk layers 3–4 are significantly larger (~ 50%) than those in S1BF L5a. Electrical Po stimulation elicits different area-specific response patterns. In S1BF, responses show weak or no facilitation, and involve both ionotropic and metabotropic glutamate receptors, whereas in M1wk, unit responses exhibit facilitation to repetitive stimulation and involve ionotropic NMDA glutamate receptors. Because of the different laminar distribution of axon terminals, synaptic bouton size and receptor mechanisms, the impact of Po signals on M1wk and S1BF, although simultaneous, is likely to be markedly different.

Calcareous sponges of the Western Indian Ocean and Red Sea.

Past taxonomic studies of Western Indian Ocean and Red Sea Calcarea have been few and sporadic (e.g. Schuffner 1877, Jenkin 1908, Row 1909, Dendy 1913, 1916, Voigt et al. 2017, 2018). Nevertheless, approximately 70 species are known from these studies for the considered region, but the descriptions of the older records often lack sufficient details for reliable identification. We studied the Western Indian Ocean Calcarea collection kept in the Naturalis Biodiversity Center. Available specimens numbered 145, collected in the Red Sea, Seychelles, Maldives, Mayotte and Rodrigues, in addition to incidental samples from Oman, the Lakshadweep Islands, the Mozambique Channel, and Eastern South Africa. Using a combination of techniques (in situ and 'on deck' photography, detailed field notes, light microscopic studies and measurements, SEM microscopy, and selected DNA sequencing) we identified 45 species, divided over the two main classes Calcinea (24 spp.) and Calcaronea (21 spp.). Not all species could be definitely assigned to an already described or a new species, as seven remained qualified as 'spec.' or 'aff.' for reasons of insufficient material or lack of details of in situ habitus. Sixteen species appeared to be new to science: Borojevia voigti sp.nov., Borojevia tubulata sp.nov., Borojevia pirella sp.nov., Clathrina rodriguesensis sp.nov., Clathrina maremeccae sp.nov., Clathrina repens sp.nov., Leucascus schleyeri sp.nov., Leucetta sulcata sp.nov., Ute insulagemmae sp.nov., Leucandra pilula sp.nov., Leucandra mozambiquensis sp.nov., Grantessa woerheidei sp.nov., Sycettusa hirsutissima sp.nov., Vosmaeropsis glebula sp.nov., Paraleucilla erpenbecki sp.nov., and Kebira tetractinifera sp.nov. For a selection of the identified species from the Western Indian Ocean and the Red Sea (30 spp.), as well as from Indonesian material (22 spp.) published previously (see Van Soest De Voogd 2015) we obtained sequences of the partial 28S gene of nuclear rDNA (C2-D2 region, cf. Voigt Wörheide 2016). The sequences of the Western Indian Ocean and Red Sea species were used to assign these to genera and families based on a phylogenetic analysis using MEGA pack vs. 06.6 for Mac of the available dataset. The Indonesian sequences supplemented by partial 28S sequences taken from the Sponge Barcode Project website and the NCBI website were included in the phylogenetic analysis to confirm the assignments. The results were compared and discussed with additional information on regional Calcarea not represented in our material. The latter chapter yielded the discovery of a preoccupied name leading to Sycon oscari nom.nov. for a species described from Mauritius.

New Methods of Morphometric Analyses on Scyphozoan Jellyfish Statoliths Including the first Direct Evidence for Statolith Growth Using Calcein as a Fluorescent Marker.

Statoliths are the only hard structures in the gelatinous bell of most scyphozoan medusae and investigations on these structures could promote investigations of the understudied population dynamics and phylogeny of jellyfish. We examined the statoliths of Aurelia aurita jellyfish of different ages by light microscopic and microtomographic measurements supplemented by scanning electron microscopy. The morphometric analyses confirmed that statolith numbers and sizes increase during jellyfish development and revealed that newly-formed statoliths had similar shapes that may change during statolith growth. Nevertheless, most statoliths had a typical compact rod shape with an aspect ratio of 1-2.5 at all ages and we suggest that the composition of statolith shapes may be taxa specific. We developed a new approach allowing exact measurements of statolith growth for the first time. The application of calcein as a fluorescent marker resulted in clear fluorescent lines within the statoliths, allowing calculations of the statolith side face growth increments (0.1 µm/day; n=252). A single-crystal analysis revealed that the calcein incubation did not affect the statolith crystal structure. In conclusion, calcein labeling is an excellent method to follow the growth of bassanite statoliths.

Termal Püskürtme Yöntemi ile Üretilmiş AISI 316L Paslanmaz Çelik Kaplamaların Karşılaştırmalı İncelenmesi

In this study, austenitic stainless steel (316L) coatings were formed using both Wire Flame Spray Forming (WSF) and High Velocity Oxy Fuel (HVOF) deposition processes after a NiCr bond layer was deposited on low carbon steel substrate. The coatings were characterized by light optical microscope (LOM) and microhardness measurements. Corrosion resistance of 316L austenitic stainless steel coatings applied onto low carbon steel via WSF and HVOF spray processes was analyzed by using the potentiodynamic polarization scanning (PDS) technique. The wear behaviour of the coatings against Al 2 O 3 ball was investigated with a reciprocating tester under dry friction conditions. It was found that the HVOF sprayed coating showed higher hardness and better wear resistance than the WSF coating. However, the overall corrosion resistance of the HVOF deposited coating was inferior to that of the WSF coating.

Measuring fibre orientation in sisal fibre-reinforced, injection moulded polypropylene – Pros and cons of the experimental methods to validate injection moulding simulation

In commercial injection moulding simulation software only tools for glass fibre-reinforced thermoplastics exist, but not for natural fibres. In our research, we adapted a simulation software for sisal fibre-reinforced polypropylene. To evaluate our simulation results, three experimental methods, to measure fibre orientation are compared to each other using injection moulded sisal fibre-reinforced polymer parts: terahertz spectroscopy, μ-CT and light microscopy measurements (LMM) of microtome sections. Terahertz spectroscopy determines the main orientation over the plate thickness, but it neglects variances of fibre orientation across the plate thickness. Using μ-CT and LMM allows measuring fibre orientation at different layers across the plate thickness and to detect a shell-core effect. Care has to be taken comparing results from μ-CT and LMM, due to their differences in the slice thicknesses. The orientation found with the μ-CT correlates well with the injection moulding simulation developed for sisal fibre-reinforced polypropylene.

Efficient preparation of high concentration cellulose solution with complex DMSO/ILs solvent

The development of a low-cost and efficient solvent for cellulose has been a longstanding challenge in the field of cellulose chemistry. In this paper, we further studied a highly effective cellulose solvent composed of a large amount of dimethyl sulfoxide (DMSO) and a small amount of 1-ethyl-3-methylimidazolium acetate ([C2mim][CH3COO]). The fact that DMSO/[C2mim][CH3COO] can dissolve cellulose more efficiently than pure [C2mim][CH3COO] was fully confirmed with a combination of polarized light microscope and turbidimetric measurements. 1H-NMR spectrographs and conductivity results indicated that an increased concentration of free [CH3COO]− was the main reason for this enhanced dissolution ability. Rheology results revealed that cellulose-DMSO/ionic liquids (ILs) solution had lower zero shear viscosity, structural viscosity index, and viscous flow activation energy, which would contribute to its outstanding spinning property compared to other cellulose solutions. These advantages combined with the low cost of this proposed complex cellulose solvent make it promising to promote its industrial applications.

Quercetin protection against ciprofloxacin induced liver damage in rats

Ciprofloxacin is a common, broad spectrum antibacterial agent; however, evidence is accumulating that ciprofloxacin may cause liver damage. Quercetin is a free radical scavenger and antioxidant. We investigated histological changes in hepatic tissue of rats caused by ciprofloxacin and the effects of quercetin on these changes using histochemical and biochemical methods. We divided 28 adult female Wistar albino rats into four equal groups: control, quercetin treated, ciprofloxacin treated, and ciprofloxacin + quercetin treated. At the end of the experiment, liver samples were processed for light microscopic examination and biochemical measurements. Sections were prepared and stained with hematoxylin and eosin, and a histopathologic damage score was calculated. The sections from the control group appeared normal. Hemorrhage, inflammatory cell infiltration and intracellular vacuolization were observed in the ciprofloxacin group. The histopathological findings were reduced in the group treated with quercetin. Significant differences were found between the control and ciprofloxacin groups, and between the ciprofloxacin and ciprofloxacin + quercetin groups. Quercetin administration reduced liver injury caused by ciprofloxacin in rats. We suggest that quercetin may be useful for preventing ciprofloxacin induced liver damage.

Susceptibility to bunch stem necrosis in grapes: A breeding screen

A breeding screen has been developed with which it is possible to predict the resistance of newbred grapevine varieties to bunch stem necrosis. The screen is based on a 5-year study of 17 commercial varieties in which it was noted that in those which are sensitive to the disorder, xylem development is relatively reduced just distal to each branch point in the peduncle so as to form a short ''bottleneck'' (DURING and LANG 1993). The procedure advocated, offers a probabilistic assessment of susceptibility to the disorder, calculated from simple light microscope measurements on a relatively small amount of material.

Reliability of rapid, semi‐automated assessment of plankton abundance, biomass, and growth rate estimates: Coulter Counter versus light microscope measurements

Here we determined (1) how accurately the semi‐automated Coulter Counter (CC) measured the abundance, volume, and growth rates of mono‐specific plankton cultures compared to light microscopy and (2) whether CC‐derived particle size‐abundance spectra of whole water samples provided a near‐real time assessment of plankton community composition. A significant, positive relationship was found between CC particle and microscope cell abundance and volume estimates for 16 phylogenetically diverse plankton species. However, abundance estimates of the 2 methods differed significantly from a 1:1 relationship, with CC counts on average 15% greater than microscopy counts. Growth rate estimates showed excellent agreement for both methods for all species and were consistent over time. No significant differences in abundance, growth rate, or size estimates were observed due to light levels (Scrippsiella trochoidea) or strain variation (Heterosigma akashiwo). CC‐based, ship‐board characterization of whole plankton communities, from Georges Bank, captured changes in size‐abundance spectra and thus provided a coarse picture of in‐situ community composition. In the laboratory, the CC appears particularly well‐suited to measuring relative changes in cell abundance, such as for growth and grazing rate measurements of mono‐specific laboratory cultures, or when predator and prey species are well separated by size differences. Although microscopy remains essential for plankton analyses, these results suggest that the CC can increase sample size, improving accuracy, and precision of studies requiring frequent sampling or high degrees of replication. Deployment of these automated techniques in the field may aid in quantifying spatial and temporal variability in plankton community structure by forthcoming ocean‐observing systems.

Deneysel Model Çalışması: 1/2-5/6 Nefrektomize ve Diyabetik Ratlarda Böbreğin Histomorfolojik ve Ultrastrüktürel Değişiklikleri

Objective: Diabetes and hypertension are often seen together and their prevalence shows large variability according to geographical, cultural, demographic, nutritional and genetic factors. These diseases affect the kidneys directly or indirectly. In this study, our aim is to compare of the effect of diabetes on kidney histomorphologically and by electron microscopic evaluation using two models of the different variations of the remnant kidney model as in surgical unilaterally nephrectomized (1/2Nx) and subtotal nephrectomized (5/6Nx) rats. Material and Methods: For this aim, six groups were created: Control, Diabetes mellitus (DM), 1/2 (right) nephrectomy, 5/6 nephrectomy, 1/2 (right) nephrectomy+DM and 5/6 nephrectomy+DM. Kidney tissues were analyzed using histomorphometric and ultrastructural analysis. Results: Renal damage has showed a very rapid progression with DM and hypertension. In 1/2 Nx group with unilateral nephrectomy, the renal damage progression is not rapid as in 5/6 Nx group, but glomerular injury increases with diabetes. Scar areas, Bowman capsule thickness, nuclei/glomerulus and glomerular diameter in DM and hypertension groups were significantly higher than control and 1/2 nephrectomy groups. 5/6 Nx+Diabetes group observed the most rapid progress overall in both light and electron microscopic measurements. Conclusion: Glomerular damage has showed a very rapid progression together with diabetes and hypertension.We think that our results wouldsupply important histomorphometric and ultrastructural data and contribute to the literature especially for the model studies of hypertension and diabetes, together and separately.

A computer-assisted microscopic analysis of bone tissue developed inside a polyactive polymer implanted into an equine articular surface.

One of the most promising applications for the restoration of small or moderately sized focal articular lesions is mosaicplasty (MP). Although recurrent hemarthrosis is a rare complication after MP, recently, various strategies have been designed to find an effective filling material to prevent postoperative bleeding from the donor site. The porous biodegradable polymer Polyactive (PA; a polyethylene glycol terephthalate - polybutylene terephthalate copolymer) represents a promising solution in this respect. A histological evaluation of the longterm PA-filled donor sites obtained from 10 experimental horses was performed. In this study, attention was primarily focused on the bone tissue developed in the plug. A computer-assisted image analysis and quantitative polarized light microscopic measurements of decalcified, longitudinally sectioned, dimethylmethylene blue (DMMB)- and picrosirius red (PS) stained sections revealed that the coverage area of the bone trabecules in the PA-filled donor tunnels was substantially (25%) enlarged compared to the neighboring cancellous bone. For this quantification, identical ROIs (regions of interest) were used and compared. The birefringence retardation values were also measured with a polarized light microscope using monochromatic light. Identical retardation values could be recorded from the bone trabeculae developed in the PA and in the neighboring bone, which indicates that the collagen orientation pattern does not differ significantly among these bone trabecules. Based on our new data, we speculate that PA promotes bone formation, and some of the currently identified degradation products of PA may enhance osteo-conduction and osteoinduction inside the donor canal.

Onlay and Inlay Bone Grafts With Platelet-Rich Plasma: Histologic Evaluations From Human Biopsies

The aim of the present study was to histomorphometrically evaluate biopsies from 1) sinus inlay bone grafts prepared with or without platelet-rich plasma (PRP) and 2) onlay bone grafts in the anterior maxilla with particulate bone and PRP or block bone without PRP after 3 months. Biopsies were retrieved with a trephine drill, and samples were processed in laboratories to result in nondecalcified cut and ground sections. Light microscopic measurements of total bone area, new bone, number of vessels, and vessel area were performed at 3 regions in each sample. Calculations of ratios of new bone to total bone and vessel area to total area were performed. There was a tendency toward higher mean values for total bone area percentage and area of newly formed bone in the PRP-treated inlay biopsies. However, there was no measurable effect on vessel formation in the PRP-treated inlay samples compared with untreated inlay samples. Particulate and PRP-treated onlay bone biopsies showed higher mean values in all measured parameters compared with block bone samples; however, no differences were statistically significant. PRP treatment may favor bone formation in grafted bone, and further research is needed to describe the outcome of PRP treatment and grafting techniques in the maxilla.

The feasibility of light microscopic measurements of intercellular spaces in squamous epithelium in the lower-esophagus of GERD patients

The study aims to determine whether light microscopy can be used to accurately measure the diameters of intercellular spaces between squamous epithelial cells in the lower esophagus, and whether changes in this outcome measure can be used as a diagnostic marker for gastroesophageal reflux disease (GERD). The study has two parts. Part 1 involves 42 asymptomatic controls and 119 patients with typical symptoms of GERD, including 58 with erosive esophagitis (EE), and 61 patients with nonerosive gastroesophageal reflux disease (NERD). All biopsies were taken from the lower esophagus. All samples were observed using an immersion objective, after which diameters were measured by computer-assisted morphometry. Part 2 involves 61 individuals who were randomly selected from part 1, including 19 controls, 13 with NERD and 29 with EE. Diameter measurements using both light microscopy and transmission electron microscopy (TEM) were performed for samples of 61 individuals. Samples from a total of 61 individuals (31 male, 30 female, mean age 44.3 ± 16.0 years) were observed using both light microscopy and TEM. Both methods showed significant differences between control and disease groups; the outcomes from the two methods had a certain correlation (r = 0.605, P = 0.000). Morphometric analysis of all 161 individuals (83 males, 78 females, mean age 41.4 ± 15.7) showed mean diameters from light microscopy to be 0.58 ± 0.16 µm for controls, 1.07 ± 0.30 µm for NERD, and 1.29 ± 0.20 µm for EE; differences between control and disease groups were significant (P<0.05). The optimal cut-off value from receiver operator characteristic analysis was 0.85 µm. Diagnoses were validated using the combination of symptoms of GERD, endoscopy, and 24 h ambulatory pH monitoring as the gold standard. At the optimal cutoff, sensitivity was 93.3% and specificity was 100%. The diameters of the intercellular spaces in squamous epithelium of lower esophagus from controls and in patients with GERD can be quantitatively measured using light microscopy. Dilated diameters can serve as a sensitive, specific, and objective indicator for diagnosis of GERD.

Relationship between Airway Basement Membrane Thickness and Lung Function Tests in Patients with Asthma

Airway remodeling is a characteristic feature of asthma. It is believed that airway remodeling affects lung function and bronchial hyper-responsiveness. Therefore, the relationship between remodeling and lung function is still a matter of extensive research. However, the results of many studies are inconsistent. The aim of the study was to assess the relationship between lung function parameters and basement membrane (BM) thickness in patients with asthma. Twenty asthma patients were chosen for the study (ten male, ten female, mean age 37 +/- 15 yrs). Ten were newly diagnosed, steroid-naive patients and the other ten were patients known to have asthma who had not been treated with steroids for at least three months. The study group was selected based on the results of: clinical assessment, allergic skin-prick tests, lung function testing and bronchial challenge with methacholine. Nine (45%) patients had chronic mild, nine (45%) had moderate and two (10%) had intermittent asthma. Mean FEV1% pred. was 83 +/- 18, mean FEV1%VC 69 +/- 9, mean FVC% pred. 101 +/- 14. All patients underwent research fiberoptic bronchoscopy with BAL and bronchial mucosal biopsies. Light-microscopic measurements of BM thickness were performed in hematoxylin-eosin stained slides of bronchial wall specimens with semi-automatic software analysis MultiScan Base 08.98. Mean BM thickness was 12.8 +/- 2.8 microm (range: 8.5-20.7 microm). No significant correlations between BM thickness and FEV1% pred., FEV1%VC, FVC% pred., RV% pred., TLC% pred., Raw (pre- and post-bronchodilator) and PC20 were observed. In our group of asthma patients, mean BM was significantly thickened. No relationship between BM thickness and lung function tests, including hyper-responsiveness, was found.

Study on transparent poly(propylene) nucleated by the “in situ” reaction products of dehydroabietic acid and sodium stearate

AbstractDehydroabietic acid (DHA), sodium stearate (NaSt), DHA/NaSt (1/1 wt/wt) mixture, the reaction products of DHA/NaSt (1/1 wt/wt) mixture after heating at 220°C for 10 min and sodium dehydroabietate (DHAA‐Na) were qualitatively analyzed by Fourier transform infrared spectrometry (FTIR) and wide angle X‐ray diffractometry (WAXD). The crystallization behavior, spherulitic morphology, optical and mechanical properties of iPP samples nucleated by DHA, NaSt, DHA/NaSt (1/1 wt/wt) mixture, and DHAA‐Na under the same concentration (0.3 wt %) were investigated by differential scanning calorimetry (DSC), polarized light microscope (PLM), optical and mechanical measurements. The results showed that an “in situ” reaction occurred between DHA and NaSt, and an effective transparent nucleating agent (DHAA‐Na) was produced during the melting blending of iPP and DHA/NaSt (1/1 wt/wt) mixture in the twin screw extruder. The crystallization onset and peak temperatures, the gloss and the mechanical properties were improved markedly; the crystallization half‐time, the spherulitic size, and the haze were reduced substantially when iPP samples are nucleated by DHA/NaSt (1/1 wt/wt) mixture. The optimum composition ratio of DHA/NaSt should be kept at ≈ 1/1 wt/wt and above 0.4 wt %/0.4 wt %. The DHA/NaSt bi‐component nucleator was effective for iPP with different MFR values. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009