RESUMO
Moony viscosity of ethylene-propylene-diene monomers (EPDMs) can have effect on the crystallization dynamics, structure, and properties of EPDM/polypropylene (PP)-based thermoplastic vulcanizates (TPVs). TPVs with two different Moony viscosities are prepared via a twin-screw extruder, respectively. Crosslinked EPDM with lower Moony viscosity has a higher crosslinking density and the nucleation effect of its crosslink point improves the crystallization ability of PP in TPV, leading to PP phase crystallization at higher temperatures. For TPV with an EPDM of higher Moony viscosity, it has higher crystallinity and the EPDM phase crystallized earlier. Synchrotron radiation studies show that the EPDM with low Moony viscosity has no obvious crystalline structure, and the prepared TPV has an obvious phase separation structure, while the TPV with higher Mooney viscosity of the EPDM does not exhibit obvious phase separation, indicating that the longer EPDM chains have better compatibility with PP in TPV, also evidenced by the almost disappearance of the PP glass transition peak in TPV, from the dynamic mechanical analysis. The longer EPDM chains in TPV provide more physical entanglement and better interaction with PP molecules, resulting in a stronger strain hardening process, longer elongation at break, and higher tensile stress in TPV.
RESUMO
BACKGROUND: Gallbladder cancer is the most common malignant tumor in the biliary system, and it is characterized by high aggressiveness and an extremely poor prognosis. Current treatment for advanced gallbladder cancer remains unsatisfactory. Here, we report a patient with advanced gallbladder cancer who was cured by multidisciplinary treatment. CASE SUMMARY: A 73-year-old male presented to our hospital with right abdominal pain for 3 d and was diagnosed with stage IVB gallbladder cancer with multiple liver metastases, peritoneum metastasis, diaphragm metastasis and lymph node metastases. The patient initially received chemotherapy, targeted therapy, 125I seed implantation and immunotherapy, as there were no specific indications for radical surgery. During these palliative therapies, the level of tumor markers gradually decreased but remained higher than the normal level, lymph node metastases gradually disappeared, and liver metastasis was gradually limited to the left liver. Finally, the patient received radical surgery with left hepatectomy, radical lymphadenectomy and partial diaphragmatic resection. To date, the patient has survived for more than six years posttreatment, the levels of tumor markers are normal, and imaging examinations show no signs of tumor recurrence. CONCLUSION: Currently, the prognosis of advanced gallbladder cancer remains unsatisfactory. A single treatment method is not sufficient for patients with advanced gallbladder cancer. Multidisciplinary individualized treatment is essential and should be utilized for advanced gallbladder cancer patients to further improve prognosis.
RESUMO
The dynamic crosslinking method has been widely used to prepare rubber/plastic blends with thermoplastic properties, and the rubber phase is crosslinked in these blends. Both polyolefin elastomer (POE) and ethylene-propylene-diene monomer rubber (EPDM) can be crosslinked, which is different from usual dynamic crosslinking components. In this paper, dynamic crosslinked POE/EPDM blends were prepared. For POE/EPDM blends without dynamic crosslinking, EPDM can play a nucleation role, leading to POE crystallizing at a higher temperature. After dynamic crosslinking, the crosslinking points hinder the mobility of POE chains, resulting in smaller crystals, but having too many crosslinking points suppresses POE crystallization. Synchrotron radiation studies show that phase separation occurs and phase regions form in non-crosslinked blends. After crosslinking, crosslinking points connecting EPDM and part of POE chains, enabling more POE to enter the EPDM phase and thus weakening phase separation, indicates that dynamic crosslinking improves the compatibility of POE/EPDM, also evidenced by a lower ß conversion temperature and higher α conversion temperature than neat POE from dynamic mechanical analysis. Moreover, crosslinking networks hinder the crystal fragmentation during stretching and provide higher strength, resulting in 8.3% higher tensile strength of a 10 wt% EPDM blend than neat POE and almost the same elongation at break. Though excessive crosslinking points offer higher strength, they weaken the elongation at break.