This study has evaluated the degradation processes which will potentially affect the reinforced concrete structures of a nuclear power generation facility during and beyond its original design life. This task was undertaken in consideration of the feasibility of extending the life of nuclear power plants beyond their current license expiration dates. Following the identification of deterioration mechanisms which are expected to occur, an inspection system was developed to correctly assess and document the condition of the reinforced concrete components during their service life. Twenty-eight out of thirty-nine possible degradation modes are deemed likely to affect Surry’s reinforced concrete structures. The majority of these modes are visually evident in their incipient stages. Currently available nondestructive testing methods were assessed to determine their applicability to detect modes which are not visually evident or to determine the extent of deterioration due to other modes. It was found that many nondestructive testing methods are currently lacking in reliability, portability, or ease of application. Consequently, the developed inspection program is based primarily on visual inspections performed by qualified inspectors. This report was prepared under the authority of Virginia Power Company in conjunction with the Surry Unit One life extension study. It is the conclusion of this report that reinforced concrete degradation will in no way impair the usefulness or safety of the concrete structures of a nuclear facility during the 40 year design life provided actions are taken to implement a concrete inspection program similar to that which is described within. This program will allow the detection of potentially critical situations thereby directing the maintenance and repair activities necessary to insure the feasibility of extended life. / Master of Science

The ability of a Doppler LIDAR (Light Detection and Ranging) system to measure the speed of a moving rail vehicle in a non-contacting manner is extended to capture the lateral and vertical irregularities of the track itself and to evaluate the rail track quality. Using two pairs of lenses to capture speed signals from both rails individually, the track speed, curvature, and lateral and vertical geometry variations on each side are determined. LIDAR lenses are installed with a slight forward angle to generate velocity signals that contain two components: 1) the left and right track speeds, and 2) any lateral and/or vertical speed caused by track motion and/or spatial irregularities. The LIDAR system collects and outputs the track information in time domain. Separating each speed component (forward, vertical, and lateral) is possible due to the inherent separation of each phenomenon with respect to its spatial/temporal frequencies and related bandwidths. For the measurements to be beneficial in practice, the LIDAR data must be spatially located along the track. A data-mapping algorithm is then simultaneously developed to spatially match the LIDAR track geometry measurements with reference spatial data, accurately locating the measurements along the track and eliminating the need for a Global Positioning System (GPS). A laboratory-grade LIDAR system with four Doppler channels, developed at the Railway Technologies Laboratory (RTL) of Virginia Tech, is body-mounted and tested onboard a geometry measurement railcar. The test results indicate a close match between the LIDAR measurements and those made with existing sensors onboard the railcar. The field-testing conducted during this study indicates that LIDAR sensors could provide a reliable, non-contact track-monitoring instrument for field use, in various weather and track conditions, potentially in a semi-autonomous or autonomous manner. A length-based track quality index (TQI) is established to quantify the track geometry condition based on the geometry data collected by the LIDAR sensors. A phenomenological rail deterioration model is developed to predict the future degradation of geometry quality over the short track segments. The introduced LIDAR's TQI is considered as the condition-parameter, and an internal variable is assumed to govern the rail geometry degradation through a deterioration rule. The method includes the historical data, current track conditions collected by the LIDAR system, and traffic data to calculate the track deterioration condition and identify the geometry defects. In addition to rail geometry inspection, a LIDAR system can potentially be used to monitor the rail surface structure and integrity. This is possible due to the fact that the Doppler shift imposed on the laser radiation reflected from a moving surface has the Doppler bandwidth broadened in proportion to the height and width of the surface features. Two LIDAR-based rail surface measures are introduced based on LIDAR measurements to identify different rail surface conditions and materials. / Ph. D.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Engineering Date submitted: 28 August 2015 / Many generator transformers were installed many years ago during the initial commissioning of Eskom’s power stations. Many of these transformers have started showing signs of significant ageing of the paper insulation and hence require regular monitoring. There are two methods that are currently being employed to assess the degree of ageing of the paper insulation in a generator transformer, which are paper sampling and furan level measurement. This dissertation investigates an alternative method of predicting the degree of ageing of the paper insulation instead of what is used currently. This method uses the Arrhenius equation that relates time and temperature to determine the degree of degradation of organic materials. The reliability of the Arrhenius estimation method is assessed by comparing the predicted DP (Degree of polymerisation) values with the measured DP values of the same transformer paper insulation. The results obtained showed that there is reasonable correlation between the DP values estimated from the Arrhenius equation and the DP values estimated from the measured furan levels. The accuracy of the prediction method is reduced when the oil temperature greatly differs from the paper insulation temperature. The application of the Arrhenius equation to estimate the ageing of paper insulation is a great milestone in the quest to predict the remaining life of a transformer. It is the only method available to do this prediction and using online temperature measurement on transformers makes the method more reliable. / MT 2017

Orientador: Edson Luiz Furtado / Banca: Marli Teixeira de Almeida Minhoni / Banca: Claudio Angeli Sansigolo / Banca: Vera Lucia Ramos Bononi / Banca: Geraldo Bortoletto Junior / Resumo: Neste trabalho foi realizado um estudo de biodegradação de tocos de Eucalyptus grandis por fungos, com o intuito de se desenvolver uma metodologia alternativa para o processo de destoca em povoamentos de Eucalyptus spp.. Para tal, foram utilizadas cinco espécies de fungos, Lentinula edodes (Berk.) Pegler, Pleurotus sajor caju (Fr.) Singer, Polyporus guiannensis Mont., Pycnoporus sangüineus e Ganoderma applanatum (Pers.) Pat., testados em laboratório e em campo. Para a avaliação da eficiência destas espécies quanto à degradação, verificou-se a velocidade de crescimento em placas de petri e em tubos contendo serragem, perdas de massa de corpos de prova de madeira e os teores de lignina, celulose e holocelulose, antes e após a ação dos fungos. As maiores médias de crescimento diário foram alcançadas por Polyporus guiannensi. Nos testes de degradação com corpos de prova, foi observada maior eficiência pelo do fungo Ganoderma applanatum. Nos testes de campo, realizados para a avaliação da degradação de tocos, os fungos anteriormente descritos foram inoculados seguindo a metodologia adaptada de inoculação utilizada no cultivo do cogumelo comestível Lentinula edodes (shiitake), em tocos do último corte, em 3 regiões distintas: Luiz Antonio, Capão Bonito e Jacareí (todas no estado de São Paulo), na presença e ausência de câmara umida. Após 5 meses da inoculação, verificou-se que para as regiões Luiz Antonio e Capão Bonito os tratamentos com câmara úmida apresentaram melhores resultados quanto à degradação dos tocos. As espécies Ganoderma aplanatum e Pycnoporus sangüineus apresentaram maior eficiência quanto à degradação dos tocos no campo. Nas condições em que se realizaram os testes de patogenicidade em plantas jovens e adultas, os fungos aqui testados não indicaram ser patogênico. / Doutor

As the world's power needs grow, the demand for power from renewable resources, such as wind or solar is increasing. One major drawback associated with these renewable resources is that the power output is dependent on environmental factors, such as cloud cover and wind speeds. This allows the possibility of either power output exceeding or falling short of forecast levels that may lead to grid instabilities. Therefore, Large Scale Energy Storage (LSES) systems are critical to store excess power when the output exceeds demand in order to supplement output power when it falls short of demand.¹ The Zinc/Bromine Redox Flow Battery (RFB) is a promising technology because of previously reported long cycle-life (CL) capability, high efficiencies, low cost materials, and scalable operating conditions.² The excellent energy storage performance of the Zinc/Bromine system was confirmed by measuring both Faradaic and Coulombic electrochemical cell efficiency dependence on temperature of a bench scale Zinc/Bromine flow cell. At room temperature, near 75% Faradaic efficiency was measured when cycling the system between 20% and 100% State of Charge (SOC), which is in good agreement with published values,³ and was measured to be over 80% efficient when operating at an elevated temperature of 50°C. To elucidate capital and operational costs, key system operation parameters especially focused on degradation mechanisms were investigated. Since deep discharge cycling is perceived as highly damaging to electrochemical systems, a system was cycled between 0% and 5% (SOC) 10,000 times. Performance was quantified by measuring the frequency factor (i[subscript 0]) and relative activation energy (α) for the reactions using Tafel scans. No statistically significant degradation or change to the electrodes was observed during the zero point cycling experiment. However, it was found that under conventional operation damage to the electrodes does accumulate, presumably due to the highly oxidative environment caused by the presence of high concentrations of dissolved bromine or tri-bromide. While the performance of both electrodes shows decreases in frequency factor attributed to the damage process, the bromide oxidation process seems to be more damaging (i.e., at the positive electrode during the charging process). Long term measurements show a degradation of the electrocatalytic parameters at an applied overpotential of 100 mV from ca. 40 mA/cm² to ca. 5 mA/cm² at the positive electrode and from ca. 20 mA/cm² to ca. 10 mA/cm² for the negative electrode. A degradation rate model was proposed to predict the service life expectancy of graphite electrodes in a bromine system based on processes showing a combined second order reaction rate coupled with a negative first order reaction rate. The model can be used to predict the cost of energy when operating any device using graphite electrodes, based on the operating power ratio, defined here as the quotient between operating power and system rated power. This damage could be partially reversed by exposing the electrode surfaces to concentrated potassium hydroxide dissolved in isopropanol, presumably due to exfoliation of the electrocatalytic surface leading to the exposure of a clean surface with electrocatalytic performance close to the original. Further, a chemical pretreatment for the graphite surface imparting enhanced stability in aqueous bromine systems was developed that shows negligible damage when similar amounts of current have passed through the electrode surface. After bromide oxidation equivalent to passing ca. 10 Ah/cm² the treated surface showed a change in steady state current density at an applied overpotential of 100 mV from ca. 50 mA/cm² to ca. 48 mA/cm². / Graduation date: 2013 / Access restricted to the OSU Community at author's request from April 1, 2013 - April 1, 2015

Sculptural works in an outdoor environment undergo different types of deterioration, depending upon their media and the environment in which they are placed. Sculptural monuments in an outdoor environment will eventually deteriorate and fail. Without proper care and the recognition of factors leading to their degradation, these sculptures will surely be lost.Delaware County retains twenty-four existing bronze and marble outdoor sculptures, many of which suffer from slight to extreme deterioration of their materials. Through research of the media, causes of deterioration, and available conservation treatments, this project strives to provide viable recommendations for prolonging the lives of these sculptures in Delaware County.Case studies of four pieces were prepared by the author, complete with photographs and surface maps that explain the type and location of deterioration present. These pieces were chosen as representative of the media surveyed. / Department of Architecture

Submitted in fulfillment of the academic requirements for the degree of Doctor of Engineering: Civil Engineering and Surveying, Durban University of Technology. Durban. South Africa, 2015. / Among various gravel roads distress prediction models in existence, a gravel loss prediction model is considered critical in selecting the optimal re-gravelling schedule for effective maintenance management of gravel roads. However, due to the number of variables contributing to deterioration of gravel roads and hence gravel loss, gravel loss prediction models are not readily transferable from one geographical location to another, particularly if the locations in question differ in climatic condition, gravel material characteristics, quality of construction and maintenance, terrain, traffic characteristics and driver behaviours. Addressing the aforementioned local characteristics pose a challenge to existing international gravel loss prediction models when employed locally, resulting in inaccurate prediction of gravel loss. Hence the need for a gravel loss prediction model to be formulated locally so as to address local characteristics influencing gravel roads deterioration. The main objective of this study was to formulate locally, a statistically accurate gravel loss prediction model for marginal gravel materials employed to surface gravel roads in Iringa region. The intention was to address local characteristics influencing gravel roads deterioration in the region. To promote research on gravel roads management, the author has published seven papers and presented ten papers in established journals and conferences respectively, as indicated in the Appendix 13. It is author expectation that, given the right impetus, locally formulated gravel loss prediction models can be incorporated, as one of a tool, in gravel roads management systems (GRMS). The literature review focused on the gravel road condition surveys, modelling exercises, gravel loss, and a review of existing gravel loss prediction models. The literature review also examined the version of GRMS currently practiced in Tanzania by its road organizations. The study used factorial experimental design. Parameters which are deemed to influence the gravel loss were collected and studied. A questionnaire was used to study the status of gravel road MMS in Tanzania. The data obtained from the questionnaire responses were analysed with the aid of Statistical Package for Social Sciences (SPSS) and Microsoft Excel. A detailed gravel road condition survey of each 300 m long test section was carried out during site visits. The measurement of gravel loss through the change in average height loss formed a crucial part of the study. The modelling of a gravel loss prediction model was performed using pavemetric principles, the term coined by this study, which is principally based on econometric principles. From the analysis of questionnaire responses, it was evident that each Tanzania Roads Agency (TANROADS) regional office and district council works department needs to have a unique MMS and GRMS which reflect their operating capacity. The results of the condition survey led to the formulation of a new range of grading coefficient (GC) to suit the local marginal materials. The gravel loss survey results assisted in establishing gravel loss thresholds. The thresholds were based on the rate of gravel loss noted in the study. These thresholds can be employed to enhance the quality control of gravel roads construction and maintenance practices. The study formulated a gravel loss prediction model for Iringa region. The process utilized average daily traffic, climate, and derivatives of sieve analysis and Atterberg limits. The model is statistically significant at 1 % level. The model gives a constant gravel loss of 0.1 mm per annum regardless the state of the six variables in the model. This was attributed to autonomous loss that is the amount of gravel material lost through mechanical and chemical weathering. Recommendations include the need for gravel loss prediction models to reflect local characteristics influencing the deterioration of the gravel roads in question and the modelling capacity of local road agencies. Areas for further studies are highlighted.

High availability of a system can be achieved by performing timely replacement of degraded or failed components. To this end, spare parts are expected to be available and reordered when needed. It is not uncommon that spare parts may deteriorate on the shelf because of their physical characteristics and/or the imperfect storage and transportation conditions. Such phenomena will affect the reliability of spare parts and the availability of the system. In this dissertation, we first focus on a system with single critical operating component and one unit of deteriorating spare part. For such a system, to ensure the system availability and cost efficiency, making a joint decision on component replacement and reordering time is of vital importance. In particular, we study both failure-switching and preventive-switching strategies, where cumulative damage is considered for the spare part switching from its in-stock to operating conditions. To determine the corresponding optimal component replacement and reordering policies, the long-run average costs are minimized under a fixed lead time. It is expected that the work will benefit quite a few industry sectors, such as mining, oil and gas, and defense, where the operation of systems heavily relies on capital-intensive components. To advance the research a step further, we have relaxed the system with only a single operating component to a more complex system with multiple components. In addition, we have eliminated the limitations on the order quantity and inventory capacity. To capture the on-shelf part deterioration, a two-phase deteriorating process is adopted, for which the first phase is from the spare's new arrival to the identification of its degradation, and the second phase is the period thereafter but before the unit fails. Based on the parts' degradation states, we introduce two different replacement strategies for the spare consumption, i.e., the Degraded-First strategy and the New-First strategy. Because of the random nature of component failures and on-shelf deterioration, stochastic cost models for both DF and NF strategies are derived. With the objective of cost reduction through coordinating the inventory and maintenance policies, an enumeration algorithm with stochastic dynamic programming is employed for finding the joint optimal solution over a finite time horizon. Numerical experiments are conducted to study the impacts of these two strategies on the operation costs, and the analysis of key parameters that affect the optimal solutions is also carried out in the numerical study. The joint policies of our interest focus on both replacement and reordering of spare parts, which are more realistic and complex than those policies handling maintenance and spare parts inventory control separately. In particular: When the maintenance planning and inventory control strategy are jointly optimized, we consider the spare parts inventory experiencing on-shelf deterioration, which has not been well studied in the related literature. When dealing with a system carrying only one spare part, the impact of on-shelf deterioration of the spare part on its remaining operational lifetime is explicitly dealt with and described by the Cumulative Exposure (CE) model. For the extended model for a multi-component system, we make an early attempt to adopt a two-phase process to take into account on-shelf degradation of parts. The issues in the degradation-level-based ordering of spare parts in the multi-component system are also discussed. Several integrated cost models are developed in both systems and are used to determine the optimal replacement and reordering decisions with the objective of minimizing the expected long-run cost rate over an infinite/finite horizon.

Thesis (MSc)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: It is commonly known that a diversity of fungi, including yeasts, may occur on plant surfaces. Similarly, on fallen trees an ecological succession of different fungal species is known to occur during wood degradation. Some of these fungi may be pioneer fungi contributing to the initial degradation process, while others may be yeasts associated with the fruiting bodies of macro-fungi which in turn are able to utilize the more recalcitrant polymers in wood. Previously, it was revealed that an increase occurs in the wood degradation rate of certain white-rot fungi when co-cultured with selected yeast species. A well known inhabitant of decomposing trees is the white rot fungus Pycnoporus sanguineus. It was found by some that this fungus is capable of selective delignification while growing on the wood of poplar trees, while other authors found a simultaneous delignification pattern on Eucalyptus grandis trees. In the latter case cellulose and lignin are degraded simultaneously. We were interested in how yeasts occurring on the surface of P. sanguineus fruiting bodies, and the pioneer fungus Aspergillus flavipes, impact on wood degradation by this white-rot fungus. Restriction Fragment Length Polymorphisms (RFLP) analyses were used to obtain an indication of the species composition of the culturable yeast community associated with fruiting bodies of P. sanguineus. The impact of the most dominant of these yeasts species, i.e. Pichia guilliermondii and Rhodotorula glutinis, as well as A. flavipes, on wood degradation by P. sanguineus was then determined by analyzing the major wood components after growth of co-cultures on hot water washed E. grandis wood chips. Co-cultures of P. sanguineus with the other fungi were prepared by inoculating the wood chips, contained in solid state bioreactors and supplemented with molasses and urea, with the an appropriate volume of fungal inoculum, resulting in an initial moisture content of 60%. After two weeks of incubation at 30°C with constant aeration, the chips were harvested. Standard protocol (TAPPI Standard Methods), commonly used by the paper and pulp industry, were then employed to determine the percentage cellulose, Klason Lignin, as well as polar and solvent-borne extractives in the chips. The resulting data were analyzed using box plots, as well as biplots. No degradation of Klason lignin was observed, while the percentage cellulose did decrease during fungal degradation. Taking into account the inherent shortcomings of the Klason Lignin determination, the results supported the findings of others that P. sanguineus shows a simultaneous delignification pattern while growing on E. grandis wood. In addition, it was found that the yeasts played no significant role in the degradation ability of P. sanguineus, while A. flavipes showed an antagonistic effect on P. sanguineus with respect to cellulose degradation. However, it was clear that the analytical methods used in this study were inadequate to accurately determine fungal degradation of wood. In addition, it was obvious that the methods used did not distinguish between fungal biomass and wood components. Nevertheless, the methods provided us with a fingerprint of each culture growing on E. grandis wood, allowing us to compare the chemical composition of the different cultures and the un-inoculated hot water washed wood chips. The question, therefore, arose whether the effect of a particular coculture, on the chemical composition of wood, differs between tree species. Consequently, chemical alterations in different tree species, induced by a P. sanguineus / A. flavipes co-culture, were investigated in the next part of the study. Wood chips originating from four tree species, i.e. Acacia mearnsii, Eucalyptus dunnii, E. grandis, and Eucalyptus macarthurii, were inoculated with this co-culture. The culture conditions and subsequent analyses of the wood components were the same as in the first part of the study. From the box- and biplots constructed from the resulting data, it was clear that the chemical composition of each tree species were altered in a different manner by the coculture. Lignin content showed an apparent increase in A. mearnsii, while E. dunnii showed a decrease in cellulose content. The results indicate that wood of different tree species are degraded in a different manner and this phenomenon should be taken into account in selecting fungi for biopulping. / AFRIKAANSE OPSOMMING: Dit is algemeen bekend dat 'n verskeidenheid fungi, insluitend giste, op plantoppervlaktes mag voorkom. Dit is ook bekend dat 'n ekologiese opeenvolging van verskillende fungusspesies tydens hout-afbraak op omgevalle bome voorkom. Van hierdie fungi mag pionierfungi wees wat bydra tot die aanvanklike afbraakproses, terwyl ander giste mag wees wat geassosieer word met die vrugliggame van makro-fungi, wat op hul beurt weer in staat is om die meer weerstandbiedende polimere in hout te benut. Dit is voorheen bekendgemaak dat daar 'n toename plaasvind in die tempo van houtafbraak deur sekere witvrot-fungi wanneer dit in ko-kulture met geselekteerde gisspesies voorkom. 'n Bekende bewoner van verrottende bome is die wit-vrotfungus Pycnoporus sanguineus. Dit is gevind dat hierdie fungus tot selektiewe delignifikasie in staat is terwyl dit op die hout van populierbome groei, terwyl ander outeurs 'n gelyktydige patroon van delignifisering op Eucalyptus grandis bome gevind het. In laasgenoemde geval is sellulose en lignien gelyktydig afgebreek. Ons was geïnteresseerd in die effek van giste op die oppervlak van vrugliggame van P. sanguineus, en die pionierfungus Aspergillus flavipes, op die houtafbraak deur hierdie wit-vrotfungus. Restriction Fragment Length Polymorphisms (RFLP) analises is gevolglik gebruik om 'n aanduiding te kry van die spesiesamestelling van die kweekbare gisgemeenskap wat met die vrugliggame van P. sanguineus geassosieer word. Die impak van die mees dominante van hierdie gisspesies, naamlik Pichia guilliermondii en Rhodotorula glutinis, asook A. flavipes, op houtafbraak deur P. sanguineus is voorts bepaal deur die analise van die belangrikste houtkomponente na die kweek van ko-kulture op E. grandis houtskyfies wat met warm water gewas is. Ko-kulture van P. sanguineus met die ander fungi is voorberei deur die houtskyfies in vaste fase bioreaktore, aangevul met melasse en ureum, te inokuleer met 'n toepaslike volume van die fungus inokulum om 'n aanvanklike voginhoud van 60% te verkry. Na twee weke se inkubasie by 30°C met konstante belugting is die skyfies ge-oes. Standaard protokol (TAPPI Standard Methods), algemeen deur die papier en pulpindustrie gebruik, is ingespan om die persentasie sellulose, Klason Lignien, asook polêre en oplosmiddel-gedraagde ekstrakte in die skyfies te bepaal. Die gevolglike data is geanaliseer deur gebruik te maak van box plots en biplots. Daar is geen afbraak van Klason Lignien bespeur nie, terwyl die persentasie sellulose wel toegeneem het tydens fungus degradasie. Met die inherente tekortkominge van die Klason Lignien bepaling inaggenome, het die resultate die bevindings ondersteun van andere wat getoon het dat P. sanguineus 'n gelyktydige delignifikasiepatroon openbaar terwyl dit op E. grandis hout groei. Daarby is dit gevind dat die giste geen beduidende rol in die afbraakvermoeë van P. sanguineus gespeel het nie, terwyl A. flavipes 'n antagonisiese effek ten opsigte van die sellulose degradering van P. sanguineus getoon het. Dit was egter duidelik dat die analitiese metodes wat in hierdie studie gebruik is, onvoldoende was om die degradering van hout akkuraat te bepaal. Daarby was dit duidelik dat die metodes nie tussen fungus biomassa en houtkomponente kon onderskei nie. Nogtans het die metodes 'n vingerafdruk verskaf van elke kultuur wat op E. grandis hout groei, wat ons toegelaat het om die chemiese samestelling van die verskillende kulture en die ongeïnokuleerde, met warm water gewasde houtskyfies te vergelyk. Die vraag het gevolglik ontstaan of die effek van 'n bepaalde ko-kultuur op die chemiese samestelling van hout van boomspesie tot boomspesie verskil. Gevolglik is die chemiese wisselinge in verskillende boomspesies, geïnduseer deur 'n P. sanguineus / A. flavipes ko-kultuur, in die volgende gedeelte van die studie ondersoek. Houtskyfies van vier boomspesies, naamlik Acacia mearnsii, Eucalyptus dunnii, E. grandis, en Eucalyptus macarthurii, is met hierdie ko-kultuur geïnokuleer. Die kultuurkondisies en daaropvolgende analises van die houtkomponente was dieselfde as in die eerste deel van die studie. Van die box- en biplots wat van die resultate getrek is, is dit duidelik dat die chemiese samestelling van elke boomspesie op 'n verskillende manier deur die ko-kulture verander is. Lignien-inhoud het ’n waarskynlike toename getoon in A. mearnsii, terwyl E. dunnii 'n afname in sellulose-inhoud getoon het. Die resultate toon dat hout van verskillende boomspesies op verskillende maniere afgebreek word en dat hierdie fenomeen in aanmerking geneem moet word wanneer fungi vir bioverpulping geselekteer word.

Thesis (DSc (Chemistry and Polymer Science))--University of Stellenbosch, 2009. / Unstabilised polyolefins are susceptible to degradation when exposed to molecular oxygen, heat, irradiation as well as chemical and mechanical stimuli. Oxidation leads to changes in molecular properties such as molecular weight, molecular weight distribution, chemical composition, chemical composition distribution and crystallisability. Conventional analytical techniques are of limited use when studying the degradation of heterogeneous materials such as impact polypropylene copolymers (ICPP). These copolymers consist of a number of components of different monomer contents, isotacticity and crystallinity, ranging from amorphous EPR to highly crystalline polypropylene. The individual components are affected differently by degradation, leading to heterogeneity within the degradation of impact copolymers. Novel analytical approaches that acknowledge the heterogeneity in sample composition are needed to study the degradation behaviour of such heterogeneous materials. This study describes the combination of fractionation and hyphenated techniques with conventional analyses for extensive structural characterisation of complex impact copolymers as well as their degradation behaviour. Temperature rising elution fractionation (TREF) coupled to conventional techniques such as size exclusion chromatography (SEC), Fourier-Transform infrared spectroscopy (FTIR), Carbon-13 nuclear magnetic resonance (13C-NMR) and differential scanning calorimetry (DSC) indicated the ICPPs in question to consist of four main components, namely ethylene-propylene random copolymers (EPR), isotactic PP (iPP), as well as semi-crystalline ethylene-propylene copolymers (EPC) and lower isotacticity PP. The degradation of an ICPP was studied by a multi-component analysis procedure consisting of TREF coupled to SEC, 13C-NMR, as well as SEC-FTIR. Results obtained by this procedure indicated the change in crystallisability of the bulk sample observed by TREF, crystallisation analysis fractionation (CRYSTAF) and DSC to be the result of the preferential degradation of the iPP phase. Degradation of ICPPs initiates within this phase where chain scission and carbonyl group insertion leads to a change in the crystallisability of iPP chains. During TREF of degraded bulk ICPPs, the degraded iPP molecules elute at lower elution temperatures, depending on their degree of degradation. The other components of the copolymer were degraded to a lesser extent. Degradation products were also found to be heterogeneously distributed across the molecular weight distribution of each fraction, with a higher concentration appearing at the low molecular weight side. The multi-component analysis procedure was also used to study the difference in degradation behaviour between ICPPs of different comonomer content, isotacticity and crystallinity. The spatial heterogeneity of degradation within ICPPs was studied by Fourier-Transform infrared microspectroscopy (FTIR-μS). A heterogeneous distribution of degradation products was found across the depth of thicker sample specimens. These results were compared to those obtained by conventional layer-by-layer milling followed by SEC, FTIR and CRYSTAF. The principles of degradation within thick samples were similar to that observed for thin films, although additional contributions by sample morphology and oxygen diffusion were detected.