Receiving of Therephthalic Acid from Polyethylene Terephthalate waste by depolymerization in the melt

The technological method of terephthalic acid receiving by depolymerization of polyethylene terephthalate (PET) in the melt has been developed as the result of research. Mechanism of depolymerization is studied by mean of DSC analysis. It was established, that PET depolymerization in melt can be reached at atmospheric pressure, and temperature range 140-160°C during a short time with the yield of terephthalic acid close to 95- 98%. Sodium or potassium hydroxide is more suitable reagents for PET depolymerization regarding technological point of view. The best found amount of alkali to be added to the polymer is 120% from stoichiometrically necessary quantity. Electrolytic method is more prominent for terephthalic acid precipitation because at the time of terephthalic acid receiving, sodium or potassium hydroxide can be regenerated by electrolysis and used in cycle. Possible use of catalyst – zinc acetate which is added into the melt to increase the degree of PET depolymerization is shown. The quantity of zinc acetate of 1% from polymer weight amount was found as optimum

Synthesis of block copolymers of varying architecture through suppression of transesterification during coordinated anionic ring opening polymerization

Well-defined di-and triblock copolymers consisting of ε-caprolactone (CL), L-lactide (LA), and trimethylene carbonate (TMC) were synthesized via "PLA first route" in coordinated anionic ring opening polymerization/copolymerization (CAROP) with tin (II) octoate as catalyst. The desired block structure was preserved by use of protective additive α-methylstyrene by preventing the transesterification side-reactions. MALDI-TOF analysis revealed that the protection mechanism is associated with α-methylstyrene and tin (II) octoate complexation. Additionally, it was shown that use of α-methylstyrene in ring opening polymerization allowed the formation of polyesters with high molar mass

Wczesne wyniki leczenia skolioz idiopatycznych z zastosowaniem gorsetu dynamicznego SpineCor

Wstęp: Skolioza idiopatyczna to trójpłaszczyznowa deformacja kręgosłupa. Leczenie uzależnione jest od wielu czynników, spośród których wielkość skrzywienia i stopień dojrzałości kostnej wydają się być najbardziej istotne. W przypadku progresujących skrzywień o kącie <40° zalecane jest stosowanie gorsetu. Dostępnych jest wiele rodzajów gorsetów, najczęściej o sztywnej konstrukcji. Gorset dynamiczny SpineCor to system elastycznych taśm, które po założeniu bezpośrednio korygują deformację kręgosłupa nieograniczając jego ruchomości. Cel pracy: Celem pracy jest przedstawienie wczesnych wyników leczenia skolioz idiopatycznych z zastosowaniem gorsetu dynamicznego SpineCor. Materiał i metodyka: Kryterium rozpoczęcia leczenia gorsetem była obecność progresującego skrzywienia kręgosłupa u chorych z dojrzałością kostną według Rissera 0-3. Aplikacja gorsetu odbywało się według założeń metody. Badaną grupę stanowiło 42 chorych, 36 dziewcząt i 6 chłopców. Wiek w chwili rozpoczęcia leczenia wynosił średnio 11,9 lat. Okres obserwacji wynosił średnio 11 miesięcy. Wyjściowy kąt skrzywienia w odcinku piersiowym wynosił średnio 33,1°, zaś w odcinku lędźwiowym 29,4°. Badana grupa została podzielona na podgrupy na podstawie: wielkości wyjściowego skrzywienia, lokalizacji skrzywienia, płci. Wyniki oceniano jako korekcję (zmniejszenie kąta o >=5°), stabilizację (zmiana kąta +/- 5°) lub progresję (zwiększenie kąta o >=5°). Wyniki: Wielkość kąta skrzywienia w ostatniej kontroli w odcinku piersiowym wyniosła średnio 29,7°, zaś w odcinku lędźwiowym 25,5°. U 21 chorych skrzywienie uległo korekcji (50%), 14 osiągnęło stabilizację (33,3%) a 7 progresję (16,6%). Najlepsze wyniki osiągnięto w grupie chorych z wyjściowym kątem <25° (p < 0,05) - 60% chorych z korekcją. Przeciwnie w grupie chorych z wyjściowym kątem >45° tylko 37,5% osiągnęło korekcję. Nie zanotowano znaczących różnic w wynikach leczenia w zależności od płci. Wnioski: Gorset SpineCor stanowi dobrą alternatywę dla sztywnych gorsetów, zwłaszcza w przypadkach małych skrzywień. Pozwala on na zachowanie ruchomości kręgosłupa. Tego typu gorset jest dobrze akceptowalny przez młodych chorych. Niezbędne są dalsze długofalowe obserwacje celem ostatecznych wniosków.Introdcution: Idiopathic scoliosis is a three-dimensional deformation of the spine. Treatment of this condition depends on many factors, with curve magnitude (Cobb angle) and skeletal maturity (Risser sign) being the most important indices. In progressing curves of <40°, bracing is recommended. Different types of braces are available, most of them are of a rigid type. The SpineCor dynamic brace is a system of elastic bands designed to directly correct the spinal column deformity without restricting motion of the spine. Aim of the paper: The aim of this paper is to present early results of adolescent idiopathic scoliosis treatment with the SpineCor brace. Material and methods: Inclusion criteria for brace the application included the presence of a progressing curve in a skeletally immature child (Risser 0 - 3). The SpineCor brace was applied according to the principles of the method. The study group comprised 42 patients: 36 girls, 6 boys. The mean age at brace application was 11.9 years. The mean follow-up was 11 months. The mean initial curve size in the whole group was 33.1° in the thoracic spine and 29.4° in the lumbar spine. The evaluated group was subsequently divided into different subgroups depending on: initial curve size, curve type and sex. Results were classified as correction (decrease of curve size of >=5°), stablisation (curve change +/- 5°) or progression (increase of curve size of >=5°). Results: Mean curve size at the final follow-up was 29.7° in the thoracic spine and 25.5° in the lumbar spine. Twenty one patients improved (50%), 14 had curve stabilisation (33.3%) and 7 progressed (16.6%). The best results were achieved in curves lower than 25° Cobb angle (p < 0.05) - 60% of patients improved. In contrast, in the over-45° group, only 37.5% of patients improved. No significant differences were found between treatment results with regard to sex. Conclusion: SpineCor brace seems to be a good alternative for rigid braces, especially in minor curves. It enables preservation of motion of the spine. This type of brace is easily accepted by young patients. Further follow-up is needed to present long-term results

Dehydrochlorination of PVC Compositions During Thermal Degradation

The polyvinylchloride (PVC) differs from other polymer materials by low thermostability. The process of dehydrochlorination takes place even at low temperatures. The purpose of this investigation was to determine the influence of different PVC additives on formation of hydrogen chloride (HCl) from thermal degradation in different gaseous fluids. It has been established that the HCl formation takes place more in nitrogen as a medium than in air medium at a given temperature, especially for the high temperature region. Dibutyl phthalate (as a plasticizer) in 25 mass % w.r.t. PVC, reduces the mass loss due to HCl formation by about 5%, which is the result of two interaction processes - between HCl and plastifier degradation products. It has been found that the addition of 5 mass % of stabilizer in PVC slows down the process of dehydrochlorination and as a result the loss of mass is 2-5% less, compared to non-stabilized samples. Calcium carbonate as a filler was found to be active above 400-500 °C and reduction in mass loss was found to be up to 15% at a temperature range of 800-900 °C. Calculation of kinetic parameters shows that the rate of dehydrochlorination depends on the composition of PVC. The activation energy of formation of HCl in air, in a temperature range of 400-600 °C has been found to be 12.7, 13.3, 16.1 kJ/mol for pure, plasticized and stabilized PVC, respectively. The results reported here shall be useful for development of methods for waste utilization and their influence on the environment

Influence of polyester fabric with infrared emissive additives on cell metabolism

Functional fabrics with effects of influencing the metabolism and energy supplying are of great interest and may extensively be applied in wellness and sport apparel. In this work, three different combinations of additives such as silicon oxide doped with 10% of iron oxide III, 10% of graphene and 10% calcium hydroxyapatite were prepared, each combination was compounded separately with polyester, and pellets were extruded with additive weight around 4%. Melt spun multifilament yarns (130D/48f) were produced from the prepared pellets. Further, three knitted fabrics from a yarn with additives and one control fabric from the yarn without additives were developed for comparison and analysis. Infrared emissivity test result showed that fabrics with functional additives have significantly higher effective emissivity (0.997 to 1.006) than the reference fabric (0.909) for wavelength 5-14 µm. Moreover, spectral emissivity of fabrics with additives are relatively high at peak human IR emission wavelength (8-14 µm). As a key signal molecule that is involved in certain physiological pathways, nitric oxide (NO) generation was assessed by co-culturing with human skeletal muscle cells (HMSCs). It is observed that selected additives in the fabric lead to 15%-40% increase of nitrite levels in muscle cells after 24 and 72 hours of exposure and the best among them were graphene containing additives. Besides, it is also discovered that additives in the fabric increase mitochondrial biogenesis, which is proved by the increase of mitochondrial copy number by a factor of 1.25. The mitochondrial biogenesis may be a possible pathway activated by nitric oxide and potentially accelerate the energy expenditure. The observations in the cell study indicated the potential biological effects of the fabric with selected functional additives

Synthesis of Diblocks Copolymers PCL-b-PLLA and Optimization of its Mechanical Characteristics

Biodegradable polymeric materials have a wide application in medicine, ecology and a number of other branches of industry. Overwhelming majority of such polymers is well exposed to the biodegradation, but they have mechanical properties which don't correspond to the requirements of application areas. As a rule, these materials possess low elasticity. In this work, optimization of mechanical properties of biodegradable polymers and the search of structure of block polymer on the basis of e-caprolactone and L-lactide with the maximal elasticity are considered. The purpose of the work is to receive the diblock polymer with mechanical properties as close as possible to elastomer for medical devices. The task is reached due to application of design of experiment with the subsequent optimization of the received results. Maximization of elongation at maximum load of received polymer is solved by the greatest possible reduction of crystallinity with a variation of molar weight of both part of diblock: polycaprolactone and polylactide. The absolute maximum of elongation at maximum load of synthesized diblock polymers is found. It is established that diblock with the following structure possesses the best mechanical properties in this class of polymers. Molar weight of the polycaprolactone block is 5000 Da while polylactide block is 7000 Da. Elongation at maximum load of this polymer was about 30%. In the second stage of our research, we try to improve the mechanical properties by making one block partly random (PCL-co-PLLA). Second block was made from homopolymer (PLLA). Maximum received elongation at break is 200%. First block of this polymer contains 25% of lactide, has molar weight of 10000 Da. Second block is the pure polylactide, with molar weight 10000 Da. All the experimental results and mathematical modeling pointing direction to maximum elongation could be achieved by multi-block structures

Synthesis of Diblocks Copolymers PCL-b-PLLA and Optimization of its Mechanical Characteristics

Biodegradable polymeric materials have a wide application in medicine, ecology and a number of other branches of industry. Overwhelming majority of such polymers is well exposed to the biodegradation, but they have mechanical properties which don’t correspond to the requirements of application areas. As a rule, these materials possess low elasticity. In this work, optimization of mechanical properties of biodegradable polymers and the search of structure of block polymer on the basis of e-caprolactone and L-lactide with the maximal elasticity are considered. The purpose of the work is to receive the diblock polymer with mechanical properties as close as possible to elastomer for medical devices. The task is reached due to application of design of experiment with the subsequent optimization of the received results. Maximization of elongation at maximum load of received polymer is solved by the greatest possible reduction of crystallinity with a variation of molar weight of both part of diblock: polycaprolactone and polylactide. The absolute maximum of elongation at maximum load of synthesized diblock polymers is found. It is established that diblock with the following structure possesses the best mechanical properties in this class of polymers. Molar weight of the polycaprolactone block is 5000 Da while polylactide block is 7000 Da. Elongation at maximum load of this polymer was about 30%. In the second stage of our research, we try to improve the mechanical properties by making one block partly random (PCL-co-PLLA). Second block was made from homopolymer (PLLA). Maximum received elongation at break is 200%. First block of this polymer contains 25% of lactide, has molar weight of 10000 Da. Second block is the pure polylactide, with molar weight 10000 Da. All the experimental results and mathematical modeling pointing direction to maximum elongation could be achieved by multi-block structures

Permanent water repellent chemical modification of cotton fabric with reagents containing aromatic rings

In this work, reagents with different amounts of aromatic rings were reacted with hydroxyl groups of cotton, aiming for washing stability and water repellency of treated cotton fabric. Different conditions of chemical transformation were considered, including the influence of carbonyl and ester chemical bonds, the quantity of aromatic ring in the reagent, and the properties of obtained cotton fabric. High contact angles were reached with the maximum of 140 o obtained at the usage of chlorotriphenylsilane. Six reagents used for cotton treatment have shown excellent washing stability, and their contact angles expressed the high water repellency of the fabric even after 10 washing cycles. Although mechanical properties of treated fabric were dropped for some samples due to the reduction of hydrogen bonds amount, stiffness of fabric decreased by up to 40 % which means softer fabric. The cotton fabric treated with reagent containing two aromatic rings exhibited the best properties of washing stability and water repellency.This work has been carried out in the Joint Innovation center of Institute for Sport Research and Sportmaster Group of Companies Pte Ltd., and financed by Sport and Fashion Management Pte Ltd