The effects of PHB-g-MA types on the mechanical, thermal, morphological, structural, and rheological properties of polyhydroxybutyrate biopolymers.

This study investigates the grafting of polyhydroxybutyrate (PHB) chains with maleic anhydride (MA) in concentrations ranging from 5 % to 10 % by weight. This process was conducted during microwave treatment and using a reactive extruder, employing benzoyl peroxide (BPO) as the initiator. The impact of these methods on PHB's overall properties was thoroughly investigated. In the study, PHB-g-MA was incorporated into neat PHB via the extrusion process at a 5 % loading rate. Notably, the mechanical properties exhibited an increase in the presence of PHB-g-MA, likely due to morphological improvements in the neat PHB, as indicated by morphological characterization. X-ray diffraction results indicated crystallinity percentages increase with the addition of MA. Differential scanning calorimetry revealed minimal variation in melting and crystallization temperatures when PHB-g-MA was included. Both storage and loss moduli were enhanced by the incorporation of PHB-g-MA, and the blends exhibited consistent tan delta values. Regarding rheological properties, the storage and loss moduli of PHB blends containing PHB-g-MA blends were observed to rise with rising frequency values. Based on these results, the microwave process was identified as the most effective method for grafting.

Biopolymer blends of polyhydroxybutyrate and polylactic acid reinforced with cellulose nanofibrils.

Poly(lactic acid) (PLA) was used in an effort to enhance the mechanical properties of poly(hydroxybutyrate) (PHB) and the blends were reinforced with cellulose nanofibrils (CNF). The conventional and dynamic mechanical, morphological, thermal and rheological properties of the obtained composite blends were determined. The results showed that the mechanical properties of neat PHB noticeably increased attributable to the good interaction between the biopolymers and CNF from the scanning electron microscopy (SEM) characterization. Thermal stability of the neat PHB was improved by adding PLA, however differential scanning calorimetry results showed that PLA created enhanced thermal properties while adding CNFs did not provide any change in the composite thermal properties. Dynamic mechanical and rheological properties of the neat PHB generally improved with both PLA and CNFs, however, it decreased at high loadings of CNFs attributed to fiber aggregations and fiber pull-out in comparison to the low loading level of CNF.

Psychological wellbeing of Turkish university students with physical impairments: an evaluation within the stress-vulnerability paradigm.

Generally, universities in developing countries offer little in the way of provisions and support (material, emotional, etc.) for disabled students. Therefore, disabled students experience considerable burdens and barriers in their educational life. This study investigated the psychological wellbeing of disabled Turkish university students by examining influences on stress-related growth and psychological distress. Disability is defined within the framework of a social model. According to this view, impairment refers to the functional limitation(s) that affect(s) a person's body, whereas disability refers to the loss or limitation of opportunities owing to social, physical or psychological obstacles. Seventy disabled university students with physical impairments were administered a questionnaire package, including a sociodemographic information sheet, Ways of Coping Questionnaire, Stress-Related Growth Scale, Multidimensional Scale of Social Support, Life Events Inventory, and Brief Symptom Inventory. Snowball sampling was used and voluntary participation was essential. The results showed that disability burden, daily hassles, and helplessness coping were significant predictors of psychological symptoms. For stress-related growth the only variable that appeared significant was problem-solving coping. The results pointed out that there may be different pathways to distress and growth. In order to decrease psychological distress and enhance growth in disabled university students, disability awareness programs, changes in the barriers in the academic and physical environments of the university campuses, and coping skills training to increase problem-focused coping and to combat helplessness may prove to be effective. Reducing daily hassles for the disabled students is likely to contribute to their wellbeing by decreasing their burdens. Also, a more disability-friendly environment is likely to be empowering for disabled university students.